1H-imidazol(4,5-b)pyridine derivatives

ABSTRACT

Ethers and esters of 1-hydroxy-2-(1,1-difluoroalkyl)-1H-imidazo(4,5-b)pyridine compounds, useful as herbicides.

CROSS-REFERENCE TO RELATED APPLICATION

This is a division of application serial no. 615,312, filed Sept. 22,1975 and issued Dec. 28, 1976 as U.S. Pat. No. 4,000,145. ApplicationSer. No. 615,312 was, in turn, a division of application Ser. No.447,116, filed Mar. 1, 1974 and issued Jan. 13, 1976 as U.S. Pat. No.3,932,428. Application Ser. No. 447,116 was a division of applicationSer. No. 236,195, filed Mar. 20, 1972, and issued June 18, 1974, as U.S.Pat. No. 3,818,022. Application Ser. No. 236,195 was acontinuation-in-part of application Ser. No. 181,638, filed Sept. 17,1971, and abandoned after the filing of application Ser. No. 236,195.Application Ser. No. 181,638 was a continuation-in-part of applicationSer. No. 100,410, filed Dec. 21, 1970, and abandoned after the filing ofapplication Ser. No. 181,638.

SUMMARY OF THE INVENTION

The present invention is directed to ethers and esters of1-hydroxy-2-(1,1-difluoroalkyl)-1H-imidazo(4,5-b)pyridine compounds.These derivatives are of the following formula: ##STR1## In the aboveand succeeding formulae throughout the present specification and claims,R¹ represents hydrogen, chlorine, fluorine, difluoromethyl,perfluoroalkyl of C₁ -C₆, or radical of the formula ##STR2## whereineach Z independently represents hydrogen or halogen and m represents 0or 1; R² represents amino, halogen, nitro, cyano, loweralkyl of C₁ -C₄,perfluoroalkyl of C₁ -C₈, --CF₂ Cl, --CF₂ H, or loweralkylsulfonyl of C₁-C₄, subject to the limitations (1) that all R² substituents togethercontain not more than 8 carbon atoms; (2) that not more than two R²symbols represent loweralkylsulfonyl groups; and (3) that where twoloweralkylsulfonyl groups are present, they are located at the 5- and7-positions; n represents an integer of from 1 to 3, both inclusive; andR³ represents

(1) alkyl of C₁ -C₈ ;

(2) alkenyl of C₂ -C₈ ;

(3) cycloalkyl of C₅ -C₆ ;

(4) benzyl;

(5) phenethyl;

(6) alkanoyl of C₂ -C₁₆ ;

(7) alkenoyl of C₃ -C₁₆ :

(8) carbamoyl of the formula ##STR3## wherein X represents oxygen orsulfur; and one R⁴ represents phenyl, loweralkyl of C₁ -C₄, orloweralkenyl of C₂ -C₄, and the other R⁴ represents hydrogen, loweralkylof C₁ -C₄, or loweralkenyl of C₂ -C₄, subject to the limitation thatboth R⁴ moieties taken together do not contain more than six carbonatoms, or both R⁴ moieties taken together represent straight-chainalkylene of C₂ -C₆, both inclusive;

(9) radical of the formulae ##STR4## wherein X is, as above, oxygen orsulfur. (10) radical of the formula ##STR5## wherein R⁵ representsmethylene, ethylene, or vinylene, and n represents 0 or 1; (11) radicalof the formulae ##STR6## wherein substituted phenyl is a phenyl radicalbearing from 1-3 substituents, each of which is independently amino,nitro, chloro, methyl, or methoxy, and R⁶ represents loweralkylene of C₁-C₄, both inclusive; (12) --SO₂ --R⁷ wherein R⁷ is loweralkyl as abovedefined, cycloalkyl of C₅ -C₆, phenyl, substituted phenyl as abovedefined, or benzyl;

(13) tetrahydro-2-pyranyl.

The compounds so defined are useful as herbicides. In addition, they canbe used as starting materials for a process which results inrearrangement or reduction depending on the reaction conditionsemployed.

DETAILED DESCRIPTION OF THE INVENTION

In the present specification and claims, the term "halogen" is employedto designate bromine, chlorine, fluorine, and iodine, only. In the caseof the loweralkyl, loweralkenyl, alkyl, alkenyl, alkanoyl, alkenoyl, andloweralkylene radicals, such radical can be branched or straight-chain.

An essential and distinguishing structural feature of the compounds ofthe present invention is the substituent at the 2-position (--CF₂ --R¹);representative such radicals include the following:

difluoromethyl

trifluoromethyl

difluorochloromethyl

pentafluoroethyl

heptafluoro-n-propyl

1,1-difluoroethyl

1,1-difluoro-n-propyl

1,1-difluoro-2-bromoethyl

1,1-difluoro-2-chloroethyl

1,1-difluoro-2,3-dichloro-n-propyl

1,1-difluoro-3-bromo-n-propyl

1,1,2-trifluoroethyl

1,1,2-trifluoro-n-propyl

1,1,2,3-tetrafluoro-n-propyl

1,1-difluoro-2-bromo-3-chloro-n-propyl

perfluoro-n-butyl

perfluoro-n-pentyl

perfluoro-n-hexyl

1,1,2,2-tetrafluoroethyl

Preferred groups are trifluoromethyl, difluoromethyl,difluorochloromethyl, 1,1,2,2-tetrafluoroethyl, and pentafluoroethyl.

The compounds of the present invention are typically crystalline solids.They are prepared in standard procedures for the derivatization ofhydroxy groups. Hence, those of the derivatives claimed herein which areethers can be prepared by those procedures discussed in chapter 6 ofSynthetic Organic Chemistry, by Wagner and Zook (John Wiley and Sons,Inc., New York, 1965). The same reference discusses various syntheticprocedures which can be employed for the synthesis of those derivativesclaimed herein which are carboxylic acid esters (chapter 14), carbamicacid esters (chapter 23), and sulfonic acid esters (chapter 37).

Generally, the compounds of the present invention are convenientlyprepared by the reaction of the corresponding 1-hydroxy compounds:##STR7## with a halide of the formula R³ --X, where X is halo, in thepresence of an alkali metal carbonate or other hydrogen halide acceptor.An inert liquid reaction medium can be used. The reaction proceeds undera wide range of temperatures, but is preferably conducted attemperatures of from -20° C. to the reflux temperature. Separation, andif desired, purification, are carried out in conventional procedures.

While the foregoing is the most general method, other methods areconvenient and may be preferred for some of the compounds. Thus, thosecarbamates of the formula ##STR8## are more readily prepared by reactingthe corresponding 1-hydroxy-1H-imidazo(4,5-b)pyridine with an isocyanateof the formula

    O═N═C--loweralkyl or loweralkenyl

The reaction is conducted in conventional procedures.

Likewise, the carboxylic ester compounds of the present invention otherthan the carbamate esters are often preferably prepared by reacting thedesired carboxylic acid as its anhydride with the corresponding1-hydroxy-1H-imidazo(4,5-b)pyridine starting compound. Furthermore, inthe case of the present compounds which are ethers, preparation issometimes preferably carried out by reaction of the1-hydroxy-1H-imidazo(4,5-b)pyridine with an olefin; this is particularlypreferred in the case of the tetrahydro-2-pyranyl ether. The alkenylethers may also be preferably prepared by addition to an alkyne.

Yet other synthetic techniques can be used in the preparation of thecompounds of the present invention; examples are the use ofN,N'-carbonyldiimidazole or N,N'-dicyclohexyldicarbodiimide (SeeReagents for Organic Synthesis, Fieser and Fieser (John Wiley and Sons,1967), pages 114 et seq. and 231 et seq., respectively.

The following examples illustrate the present invention and will enablethose skilled in the art to practice the same.

EXAMPLE 11-METHOXY-6-CHLORO-2-(TRIFLUOROMETHYL)-1H-IMIDAZO-(4,5-b)PYRIDINE

1-Hydroxy-6-chloro-2-(trifluoromethyl)-1H-imidazo-(4,5-b)pyridine (5grams), 80 milliliters of acetone, 5 milliliters of methyl iodide, and10 grams of anhydrous potassium carbonate were mixed, heated andrefluxed with stirring for twelve hours. The reaction mixture was thenfiltered, evaporated and eluted off of a silica column with diethylether, yielding the desired1-methoxy-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridineproduct. It was recrystallized from petroleum ether (boiling at 60°-80°C.). The product so obtained melted at 91°-2° C.

Analysis, Calc.: C, 38.20; H, 1.99; N, 16.70. Found: C, 37.92; H, 2.32;N, 16.75.

EXAMPLE 21-BENZYLOXY-6-CHLORO-2-(TRIFLUOROMETHYL)-1H-IMIDAZO-(4,5-b)PYRIDINE

1-Hydroxy-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine (5grams), 10 milliliters of benzyl bromide, 20 grams of anhydrouspotassium carbonate, and 100 milliliters of ethanol were mixed, heatedto reflux, and refluxed for 1 hour. The reaction mixture was thenfiltered, evaporated under vacuum, and extracted with diethyl ether. Theextract was filtered and evaporated under vacuum yielding a dark oilwhich on standing crystallized as the desired1-benzyloxy-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine. Itwas recrystallized from a mixture of acetone and petroleum ether boilingat 60°-80° C., m.p., 107°-09° C.

Analysis, Calc.: C, 51.31; H, 2.77; N, 12.82. Found: C, 51.54; H, 2.62;N, 13.12.

EXAMPLE 31-ACETOXY-6-CHLORO-2-(TRIFLUOROMETHYL)-1H-IMIDAZO(4,5-b)PYRIDINE

1-Hydroxy-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine (5grams), 25 milliliters of acetic anhydride and 0.1 milliliter ofsulfuric acid were mixed with stirring at 25° C. for 15 minutes. Thereaction mixture was then heated to reflux and refluxed for one-halfhour, poured into ice with stirring, stirred for ten minutes andfiltered. Filtration yielded the desired1-acetoxy-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine productas a solid. It was taken up in ether, dried over magnesium sulfate, andthe ether evaporated. The product then melted at 103°-04° C.

Analysis, Calc.: C, 38.65; H, 1.80; N, 15.02. Found: C, 38.88; H, 1.92;N, 15.02.

EXAMPLE 41-OCTANOYLOXY-6-CHLORO-2-(TRIFLUOROMETHYL)-1H-IMIDAZO(4,5-b)PYRIDINE

To 1-hydroxy-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine(2.37 grams) in 5 milliliters of pyridine was added octanoyl chloride(1.63 grams). The addition was carried out portionwise with stirring andresulted in the precipitation of a white solid. The reaction mixture wasset on a steam bath for twenty minutes, then poured over ice coldaqueous HCl. An oil separated and subsequently crystallized on vigorousstirring. This precipitate was removed by filtration, dissolved inether, dried over magnesium sulfate, filtered, and ether removed byevaporation under vacuum. The substance was purified by distillation,m.p., 33.5°-35.5° C.

Analysis, Calc.: C, 49.52; H, 4.71; N, 11.55. Found: C, 49.81; H, 4.93;N, 11.29.

EXAMPLE 51-(ALLYLCARBAMOYLOXY)-6-CHLORO-2-(TRIFLUOROMETHYL)-1H-IMIDAZO(4,5-b)PYRIDINE

1-Hydroxy-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine (4.6grams) was dissolved in 10 milliliters of diethyl ether and 2.4milliliters of allyl isocyanate added and the reaction mixture stirredat room temperature for 36 hours. The reaction mixture was then filteredyielding 4.75 grams of a white powder, the desired1-(allylcarbamoyloxy)-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.An additional portion of the product was obtained by evaporating thefiltrate. The combined products were recrystallized from a mixture ofdiethyl ether and petroleum ether boiling at 60°-80° C., m.p., about210° C.

Analysis, Calc.: C, 41.20; H, 2.51; N, 17.47. Found: C, 41.42; H, 2.51;N, 17.25.

EXAMPLE 61-(METHYLSULFONYLOXY)-6-CHLORO-2-(TRIFLUOROMETHYL)-1H-IMIDAZO(4,5-b)PYRIDINE

1-Hydroxy-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine (5grams) in 15 milliliters of pyridine was cooled to 5° C. with stirringand methylsulfonyl chloride (5 milliliters) was added in 1-milliliterportions, maintaining the temperature at about 5° C. After the additionwas completed, the reaction mixture was stirred for 2 hours at 5°-10°C., then poured into 30 grams of ice and 20 milliliters of concentratedhydrochloric acid. The desired1-(methylsulfonyloxy)-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridineproduct precipitated and was separated by filtration and washed withwater. The washed product was taken up in diethyl ether with a trace ofacetone, dried over magnesium sulfate and the solvent evaporated undervacuum. The product so obtained melted at 136.7° C.

Analysis, Calc.: C, 30.44; H, 1.60; N, 13.31. Found: C, 30.48; H, 1.83;N, 13.00.

EXAMPLE 71-METHOXY-6-AMINO-5,7-DIBROMO-2-(TRIFLUOROMETHYL)-1H-IMIDAZO(4,5-b)PYRIDINE

6-Amino-5,7-dibromo-2-trifluoromethyl-1-hydroxy-1H-imidazo(4,5-b)pyridine(1 gram) was mixed and stirred for two hours with 2 milliliters ofmethyl iodide, 2 grams of potassium carbonate, and 10 milliliters ofacetone. The reaction mixture was then diluted with about 80 millilitersof ether and washed with five 15-milliliter portions of water. The etherlayer was dried over magnesium sulfate and filtered with carbon, and theether removed on a rotary evaporator. The resulting1-methoxy-6-amino-5,7-dibromo-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridineproduct melted at 169°-72° C. A portion was recrystallized frommethanol, m.p., 177°-8° C.

Analysis, Calc.: C, 24.64; H, 1.29; N, 14.37. Found: C, 24.96; H, 1.51;N, 14.48.

EXAMPLE 81-(METHYLCARBAMOYLOXY)-6-CHLORO-5,7-DIBROMO-2-(TRIFLUOROMETHYL)-1H-IMIDAZO(4,5-b)PYRIDINE

6-Chloro-5,7-dibromo-1-hydroxy-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine(0.9 grams) was mixed with ether (15 milliliters) and methyl isocyanate(2 milliliters) and stirred for fifteen minutes. Triethylamine (0.01milliliter) was added, and the solution became homogenous. It waspermitted to stand for sixteen hours, diluted with 50 millilitersdiethyl ether; washed with 0.5N HCl, water, and saturated NaCl; thendried over magnesium sulfate, and evaporated. The resulting1-(methylcarbamoyloxy)-6-chloro-5,7-dibromo-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridineproduct was recrystallized from chloroform, m.p., 216° C.

Analysis, Calc.: C, 23.89; H, 0.89; N, 12.38. Found: C, 23.82; H, 0.90;N, 12.16.

EXAMPLES 9-61

Other representative compounds of the present invention, prepared inaccordance with the foregoing teachings, include the following:

1-allyloxy-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine, n_(D)²³.5 1.5204.

1-isopropoxy-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine,m.p., 49°-51° C.

1-ethoxy-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine, n_(D)²⁵ 1.5082.

1-(methylcarbamoyloxy)-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine,m.p., 267° C.

1-(2-methoxy-3,6-dichlorobenzoyloxy)-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine,m.p., 148°-9° C.

1-ethoxy-2,6-bis(trifluoromethyl)-1H-imidazo(4,5-b)pyridine, n_(D) ²⁵1.5100.

1-methoxy-6-nitro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-n-octyloxy-6-(methylsulfonyl)-2-(heptafluoro-n-propyl)1H-imidazo(4,5-b)pyridine.

1-n-butoxy-6-fluoro-2-(1,1-difluoroethyl)-1H-imidazo(4,5-b)pyridine.

1-phenethoxy-2,6-bis(chlorodifluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-vinyloxy-2,6-bis(difluoromethyl)1H-imidazo(4,5-b)pyridine.

1-(dimethylcarbamoyloxy)-6-bromo-2-(perfluoro-n-hexyl)-1H-imidazo(4,5-b)pyridine.

1-methacryloyloxy-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-lauroyloxy-2,6-bis(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-(2,4-dichlorophenoxyacetoxy)-6-chloro-2-(trifluoromethyl)1H-imidazo(4,5-b)pyridine.

1-benzoyloxy-2,6-bis(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-(phenylacetoxy)-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-(3-phenylpropionyloxy)-6-(methylsulfonyl)-1-H-imidazo(4,5-b)pyridine.

1-cinnamoyloxy-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-(2,4,5-trichlorophenoxy)propionyloxy)-6-chloro-2(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-cyclohexyloxy-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-(phenylsulfonyloxy)-2,6-bis(difluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-(benzylsulfonyloxy)-6-chloro-2-(difluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-(cyclohexylsulfonyloxy)-6-nitro-2-(trifluoromethyl)-1-H-imidazo(4,5-b)pyridine.

1-((p-chlorophenyl)sulfonyloxy)-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-(2-butenyloxy)-6-(isopropylsulfonyl)-2-(1,1-difluoro-3-chloropropyl)-1H-imidazo(4,5-b)pyridine.

1-(6-octenyloxy)-6-chloro-2-(trifluoromethyl)-1-H-imidazo(4,5-b)pyridine.

1-(9-hexadecenoyloxy)-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-(isopropylthiocarbamoyloxy)-6-chloro-2-(pentafluoroethyl)-1H-imidazo(4,5-b)pyridine.

1-(3-amino-2,5-dichlorobenzoyloxy)-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-(2,5-dichloro-3-nitrobenzoyloxy)-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-(2-(4-chloro-o-tolyloxy)acetoxy)-2,6-bis(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-(tetrahydro-2-pyranyloxy)-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-methoxy-2,6-bis(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-(methylcarbamoyloxy)-2,6-bis(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-(2-methoxy-3,6-dichlorobenzoyloxy)-6-amino-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-(methylsulfonyloxy)-6-nitro-5,7-dibromo-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-(2-(4-chloro-o-tolyloxy)acetoxy)-5-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-(2,4-dichlorophenoxyacetoxy)-7-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-methoxy-5-(methylsulfonyl)-2-(pentafluoroethyl)-1H-imidazo(4,5-b)pyridine.

1-ethoxy-7-fluoro-2-(difluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-propionyloxy-5-chloro-6-bromo-2-(1,1,2,2-tetrafluoroethyl)-1H-imidazo(4,5-b)pyridine.

1-octanoyloxy-7-amino-2-(difluorochlormethyl)-1-H-imidazo(4,5-b)pyridine.

1-methoxy-7-nitro-2-(difluorochloromethyl)-1H-imidazo(4,5-b)pyridine.

1-allyloxy-2,7-bis(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-cyclohexyloxy-5,6,7-trinitro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-benzyloxy-5,6,7-trichloro2-(difluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-phenethoxy-5,6-bis(difluoromethyl)-2-(trifluromethyl)-1H-imidazo(4,5-b)pyridine.

1-acetoxy-2,5,6-tris(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-acryloyloxy-5,6-bis(difluorochloromethyl)-1H-imidazo(4,5-b)pyridine.

1-(tetrahydro-2-pyranyloxy)-5,6-bis(ethylsulfonyl)-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-benzoyloxy-6-methyl-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.

1-methoxy-6-(perfluorooctyl)-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.

The compounds of the present invention are adapted to be employed asherbicides. The compounds can be utilized to achieve broad herbicidalaction; hence, in its broadest sense, the present invention is directedto a method which comprises applying to a plant part, which can be astem, leaf, flower, fruit, root, or seed or other similar reproductiveunit of a plant, a growth-inhibiting amount of one of the compounds ofthe present invention. However, the compounds can also be utilized totake advantage of selective patterns of herbicidal activity.

It is not critical to the practice of the present invention thatcomplete destruction of undesirable vegetation be obtained, it beingadequate if the growth of the unwanted vegetation is merely inhibited.Especially where selective action is sought, inhibition falling short ofactual killing is adequate, particularly when combined with naturallyoccurring conditions such as limited moisture and the like which moreadversely affect the vegetation selectively inhibited than the cropplant.

The compounds of the present invention are suited to a wide variety ofherbicidal applications. Thus, for example, at rates which evoke theselective action of the compounds, which rates are defined morecompletely hereinbelow, the compounds can be used as selectiveherbicides in crop plants, such as, for example, cotton, corn, sorghum,soybeans, and the like. In such use, application can be made preemergentto both crops and weeds, or, preferably by means of a directed sprayapplication technique postemergent to the crop plant but bothpreemergent and postemergent to the weeds. In another application, thecompounds can be used to give broad herbicidal action on non-crop land,including intermittently non-crop strips of contour-farmed land. Forsuch usage on so-called fallow land, application can be made in springto suppress vegetative growth until a fall or following spring planting,or in the fall to suppress vegetative growth until a spring or followingfall planting. Furthermore, in another application, the presentcompounds can be utilized to control weeds in tree crop plantings, suchas plantings of the various citrus trees. In all of these variousapplications, and yet others for which the present compounds are suited,another advantage is that the compounds need not be disced into the soilbeing treated, it being adequate if one of the compounds, or aformulation containing one of the compounds, is merely spread onto thetop surface. However, where desired for convenient, the compounds can bedisced into, or otherwise mechanically mixed with the soil. In additionto the foregoing terrestrial embodiments, the present compounds can alsobe utilized as aquatic herbicides.

The practice of the present invention in any of its numerous embodimentscan in some instances be carried out with unmodified compound; however,for good results, it is generally necessary that the compound beemployed in modified form, that is, as one component of a compositionformulated to implement the plant growth-inhibiting effects. Thus, forexample, the active agent can be mixed with water or other liquid orliquids, preferably aided by the usage of a surface active agent. Theactive agent can also be incorporated on a finely divided solid, whichcan be a surface active substance, to yield a wettable powder, which cansubsequently be dispersed in water or other liquids, or incorported aspart of a dust which can be applied directly. Other methods offormulations are known in the art and can be employed in implementingthe present invention.

In carrying out the novel method of the present invention, the exactamount of the active agent employed is not critical and will vary,depending upon the type of growth-inhibiting effect desired, theidentity of the plants concerned, the particilar active agent used,weather conditions, and the like. In general, a broad growth-inhibitingeffect is obtained with rates of from 3-5 to 20 pounds or more of activeagent per acre, and such rates are suitable and effective for control ofvegetative growth on fallow land. When it is desired to obtain aselective growth-inhibiting effect on weeds in areas containing cropplants such as corn, soybeans, and cotton, rates of from 0.25 or less to5 pounds generally give good results. When in the typical mode ofoperation, the active agent is employed as a composition comprising theagent, the exact concentration of active agent in the composition is notcritical, except that the concentration and total amount of formulationemployed be adequate to supply the appropriate amount of active agent ona per acre basis. In general, good results are obtained when employingformulations containing the active agent in a concentration of from 0.5to 10 percent or higher, in the instance of a liquid formulation; and ina concentration of from 1.0 to 5.0 percent or higher, in the instance ofa dust, powder, granule, or the like. More concentrated formulations canbe prepared and are often preferred in that they can serve, dependingupon the particular application contemplated and the particularconcentration, both as a concentrated formulation for purposes ofshipment, storage, and the like, and as an ultimate treatingcomposition. Thus, for example, formulations often preferably contain asurface active agent and the present active agent, the latter beingpresent in an amount of from 0.5 to 99.5 percent, by weight; or aninert, finely divided solid and the present active agent, the latterbeing present in an amount of from 1.0 to 99.0 percent, by weight. Suchformulations, as indicated, can be employed directly in certainapplications, but can also be diluted and subsequently employed in manyother applications.

Liquid compositions containing the desired amount of active agent areprepared by dissolving the substance in a liquid with or without the aidof a surface active dispersing agent such as an ionic or non-ionicemulsifying agent. Most preferably, the subject compound is dissolved inwater or in an organic liquid carrier, aided by the use of a surfaceactive dispersing agent. Suitable such organic liquid carriers includeagricultural spray oils and the petroleum distillates such as dieselfuel, kerosene, fuel oil naphthas and Stoddard solvent. The choice ofdispersing and emulsifying agent and the amount thereof employed isdictated by the nature of the composition and by the ability of theagent to facilitate the dispersion of the active agent in the carrier toproduce the desired composition. Dispersing and emulsifying agents whichcan be employed in the compositions include the condensation products ofalkylene oxides with phenols and organic acids, alkyl aryl sulfonates,polyoxyalkylene derivatives or sorbitan esters, complex ether alcohols,and the like. Representative surface active agents which are suitablyemployed in implementing the present invention are identified in U.S.Pat. Nos. 3,095,299, second column, lines 25-36, 2,655,447, column 5,and 2,412,510, columns 4 and 5.

In the preparation of dust compositions, the active ingredient isintimately dispersed in and on a finely divided solid such as clay,talc, chalk, gypsum, limestone, vermiculite fines, perlite, and thelike. In one method of achieving such dispersion, the finely dividedcarrier is mechanically mixed or ground with the active agent.

Similarly, dust compositions containing the toxicant compounds can beprepared with various of the solid surface active dispersing agents suchas bentonite, fuller's earth, attapulgite and other clays. Dependingupon the proportions of ingredients, these dust compositions can beemployed as concentrates and subsequently diluted with additional solidsurface active dispersing agents or with chalk, talc, or gypsum and thelike to obtain the desired amount of active ingredient in a compositionadapted to be employed for the suppression of the growth of the plants.Also, such dust compositions can be dispersed in water, with or withoutthe aid of a dispersing agent, to form spray mixtures.

Formulations containing the present active agent are oftenadvantageously further modified by incorporation therein of an effectiveamount of a surfactant which facilitates the dispersion and spreading ofthe formulation of the plant leaf surfaces and the incorporation of theformulation by the plant.

In accordance with the present invention, the active agent can bedispersed in soil or other growth media in any convenient fashion.Applications can be carried out by simply mixing with the media, byapplying to the surface of soil and thereafter dragging or discing intothe soil to the desired depth, or by employing a liquid carrier toaccomplish the penetration and impregnation. The application of sprayand dust compositions to the surface of soil, or to plant parts or theabove ground surfaces of plants can be carried out by conventionalmethods, e.g., power dusters, boom and hand sprayers and spray dusters,whether surface or air-borne. However, while such conventional modes ofapplication can be used, they are not required. As above noted, it is anadvantage of the present invention that the compounds serving as activeagent are active and effective as herbicides when merely placed on thesurface of the soil, without any additional step to assistincorporation. Thus, the compounds are of substantially the sameefficacy regardless of whether they are applied to the surface only, orwhether they are applied to the surface and subsequently disced into thesoil.

In a further method, the distribution of the active agent in soil can beaccomplished by introducing the agent into the water employed toirrigate the soil. In such procedures, the amount of water is variedwith the porosity and water holding capacity of the soil to obtain adesired depth of distribution of the agent.

In addition, the present method also comprehends the employment of anaerosol composition containing one or more of the present active agentsas an active compound. Such a composition is prepared according toconventional methods wherein the agent is dispersed in a solvent, andthe resultant dispersion mixed with a propellant in liquid state. Suchvariables as the particular agent to be used and the nature of thevegetation which is to be treated will determine the desirability of thesolvent and concentration of the agent therein.

Satisfactory results are obtained when the active agent of the presentinvention, or a composition comprising such active agent, is combinedwith other agricultural materials intended to be applied to plants,plant parts, or their habitats. Such materials include fertilizers,fungicides, nematocides, insecticides, other herbicides, soilconditioning agents, and the like.

The following further examples illustrate the herbicidal utility of thecompounds of the present invention.

EXAMPLES 62-70:

Various of the compounds of the present invention were evaluated forpreemergent application to various crop and weed species. Each compoundwas formulated by dissolving it in a 1:1 mixture of acetone and ethanolcontaining a small amount of a blend of sulfonate nonionic emulsifyingagents; the solution was then diluted first with deionized water, thenserially with deionized water containing 1000 ppm. of the blend ofemulsifiers. The resulting solutions contained the subject compound invarious amounts, the emulsifier blend in a concentration of 0.1 percent,and the acetone and ethanol each in a concentration of 4.0 percent.

A soil was prepared consisting of one part masonry sand and one partshredded top soil blended together in a cement mixer. One gallon of thissoil was placed in a 21.5 × 31.5 cm. galvanized flat and was patted downwith a bench brush until level. A three-row marker was used to make 21/2cm. deep furrows in approximately two-fifths of the flat. Crop seedsconsisting of four kernels of corn, five cotton seeds and five soybeanseeds were placed in these furrows. A four-row template was then placedon the remaining soil and the indicated approximate numbers of each ofthe following seeds were planted, one species to each section: foxtail(millet), 80-100 seeds; velvetleaf (40-50 seeds); rough pigweed (150-250seeds); and large crabgrass (100-150 seeds).

Sufficient soil was added to cover the entire flat. Thus, the weed seedswere covered to a depth of about 6 mm. and the crop seeds were coveredto a depth of about 3 cm.

In assaying the effect of the composition as preemergent herbicides, aflat prepared as above, taken either on the day of planting or on thenext day, was placed in a chamber equipped with a turntable and an airexhaust. The herbicidal composition was applied to the flat with amodified DeVilbiss atomizer hooked to an air source. Twelve and one-halfmilliliters of the composition under test were applied to each flateither on the day of planting or on the succeeding day. Injury ratingsand observations as to type of injury were made 11 to 12 days aftertreatment. The injury rating scale used was as follows:

O--no injury

1--slight injury

2--moderate injury

3--severe injury

4--death

When more than one determination was carried out at a given rate, anaverage value was calculated for the injury rating.

In the following table setting forth the results of the evaluation,column 1 gives the name of the compound under test; column 2, the ratein pounds per acre at which the compound was applied to the test flat;and the remaining columns, the injury to the particular plant seeds orseedlings as measured by the foregoing scale.

                                      TABLE I                                     __________________________________________________________________________    Injury Rating on Preemergent Treatment                                                     Lbs./                          Velvet-                           Compound     Acre                                                                             Corn                                                                              Cotton                                                                            Soybean                                                                            Crabgrass                                                                           Pigweed                                                                            Foxtail                                                                           leaf                              __________________________________________________________________________    1-Methoxy-6-chloro-2-                                                                      8  2   4   3    3     3    4   3                                 (trifluoromethyl)-1H-                                                                      4  2   2   1    4     4    4   4                                 imidazo(4,5-b)pyridine                                                                     2  1   1   1    4     3    4   4                                              1  0   1   0    3     3    3   4                                 1-Acetoxy-6-chloro-2-                                                                      8  1   --  --   3     2    3   3                                 (trifluoromethyl)-1H-                                                                      4  1   0   0    2     2    3   3                                 imidazo(4,5-b)pyridine                                                                     2  0   0   1    1     2    3   3                                 1-Ethoxy-6-chloro-2-                                                                       8  3   --  --   3     4    4   --                                (trifluoromethyl)-1H-                                                                      4  0   0   1    4     3    4   --                                imidazo(4,5-b)pyridine                                                                     2  0   0   0    3     2    2   --                                1-Allyloxy-6-chloro-2-                                                                     8  3   --  --   4     4    4   --                                (trifluoromethyl)-1H-                                                                      4  1   0   0    4     3    4   --                                imidazo(4,5-b)pyridine                                                                     2  0   0   0    3     1    3   --                                1-Isopropoxy-6-chlor-2-                                                                    8  2   --  --   4     4    4   --                                (trifluoromethyl)-1H-                                                                      4  1   0   1    4     2    4   --                                imidazo(4,5-b)pyridine                                                                     2  0   0   0    2     1    3   --                                1-(Allylcarbamoyloxy-6-                                                                    8  2   --  --   3     3    4   --                                chloro-2-(trifluoro-                                                                       4  0   1   1    3     3    2   --                                methyl)-1H-imidazo-                                                                        2  1   2   1    2     0    2   --                                (4,5-b)pyridine                                                               1-Octanoyloxy-6-chloro-                                                                    8  2   --  --   3     4    4   --                                2-(trifluoromethyl)-1H-                                                       imidazo(4,5-b)pyridine                                                                     4  1   4   1    4     2    4   --                                1-(Methylcarbamoyloxy)-                                                                    8  1   --  --   3     3    4   --                                6-chloro-2-(trifluoro-                                                                     4  1   2   1    3     3    4   --                                methyl)-1H-imidazo-                                                                        2  0   1   1    1     3    4   --                                1-Methoxy-5-chloro-2-                                                                      8  3   --  --   4     4    4   4                                 (trifluoromethyl)-1H-                                                                      4  2   0   2    3     3    4   4                                 imidazo(4,5-b)pyri-                                                                        2  0   0.5 --   3     3.5  3.5 4                                 dine                                                                          __________________________________________________________________________     NOTE: Dashes indicate species which were not tested.                     

EXAMPLES 71-76:

Representative compounds of the present invention were evaluated forpostemergent application to plants including corn and several weedspecies. The evaluation was carried out in accordance with theprocedures of Examples 62-70 except that the test solutions were appliedabout 9-12 days after the preparation and seeding of the flat. Theresults are as set forth in the following table:

                  TABLE II                                                        ______________________________________                                        Injury Rating on Postemergent Treatment                                                    Lbs./         Crab- Pig- Fox- Velvet-                            Compound     Acre   Corn   grass weed tail leaf                               ______________________________________                                        1-Acetoxy-6-chloro-2-                                                                      8      4      4     4    4    4                                  (tri-fluoromethyl)-1H-                                                                     4      4      4     4    4    4                                  imidazo-     2      4      4     4    4    4                                  (4,5-b)pyridine                                                                            1      2      4     4    4    4                                  1-Ethoxy-6-chloro-2-                                                                       3      4      4     4    4    4                                  fluoromethyl)-1H-                                                                          4      4      4     4    4    4                                  imidazo-     2      2      4     4    4    4                                  (4,5-b)pyridine                                                                            1      1      4     4    3    4                                  1-(3,6-Dichloro-2-                                                                         8      1      4     4    3    3                                  6-chloro-2-(tri-fluoro-                                                       methyl)-1H-imidazo-                                                           (4,5-b)pyridine                                                                            4      0      3     2    3    3                                  1-(Methylcarbamoy-                                                                         8      2      4     4    4    4                                  loxy)-6-chloro-2-(tri-                                                                     4      2      4     4    4    3                                  fluoromethyl)-1H-                                                                          2      2      4     4    3    4                                  imidazo(4,5-b)pyridine                                                                     1      1      3.5   4    4    2.5                                1/2          0      4      3     4    2                                       1/4          0      4      3     3    2                                       1-Methoxy-6-amino-5,                                                                       8      0      3     4    3    2                                  7-dibromo-2-(trifluoro-                                                       methyl)-1H-imidazo-                                                           (4,5-b)-pyridine                                                              1-(Methylcarbamoy-                                                                         8      3      4     4    4    4                                  loxy)-6-chloro-5,7-di-                                                        bromo-2-(tri-fluoro-                                                          methyl)-1H-imidazo-                                                           (4,5-b)pyridine                                                               ______________________________________                                    

Essentially the same results as those reported in foregoing Examples62-76 are obtained when evaluating the other representative compounds ofExamples 1-61 hereinabove.

EXAMPLES 77-87

Other studies were carried out, evaluating various compounds of thepresent invention for preemergent application. These studies were madewith a greater variety of plant species, at lower rates of application.Formulation of the compounds, however, was carried out in the samemanner as described in preceding examples.

Rating of the herbicidal effect was on a scale of 0-10with 0 indicatingno herbicidal effect, and 10 indicating nonemergence or death. Inaddition, the kind of herbicidal effect was observed and recorded inaccordance with the following notation system:

A = abscission of leaves

B = burned

C = chlorosis

D = death

E = epinasty

F = formative effects other than epinasty

G = dark Green

I = increased plant growth

L = local necrosis

N = no germination

P = purple pigmentation

R = reduced germination

S = stunting

U = unclassified injury

                                      TABLE III                                   __________________________________________________________________________                                                         Fox-                                                              Morn-    Vel-                                                                             tail                                                                             Barn-                                 Lbs./     Soy-  Pea-  Soy-                                                                             ing-                                                                              Cockle-                                                                            vet-                                                                             Mil-                                                                             Rag-                                                                             yard               Compound        Acre                                                                             Corn                                                                             Cotton                                                                            bean                                                                             Rice                                                                             nut                                                                              Corn                                                                             bean                                                                             glory                                                                             bur  leaf                                                                             let                                                                              weed                                                                             Grass              __________________________________________________________________________    1-Methoxy-6-chloro-2-                                                                         0.5                                                                              2SC                                                                              0   0  0  0  0  0  10D 4BC  3BC                                                                              5BC                                                                              8BC                                                                              8BC                (trifluoromethyl)-1H-                                                                         1.0                                                                              4SC                                                                              3B  5BC                                                                              4BC                                                                              0  2SC                                                                              3CB                                                                              10D 10D  7BC                                                                              9BC                                                                              10D                                                                              9BC                imidazo(4,5-b)pyridine                                                                        2.0                                                                              5SC                                                                              7BC 9BC                                                                              6BC                                                                              3C 4SC                                                                              8CB                                                                              10D 10D  10D                                                                              10D                                                                              10D                                                                              9.5BC              1-Acetoxy-6-chloro-2-                                                                         0.5                                                                              0  0   0  0  0  0  0  10D --   4BC                                                                              4BC                                                                              8BC                                                                              2BC                (trifluoromethyl)-1H-                                                                         1.0                                                                              4SC                                                                              6BC 5BC                                                                              4BC                                                                              0  3SC                                                                              6BC                                                                              10D 10D  8BC                                                                              5BC                                                                              10D                                                                              4BC                imidazo(4,5-b)pyridine                                                                        2.0                                                                              5SC                                                                              10D 10D                                                                              7BC                                                                              3C 6SC                                                                              9BC                                                                              10D 10D  9BC                                                                              9.5                                                                              10D                                                                              8.5BC                                                                   BC                       1-Ethoxy-6-chloro-2-                                                                          0.5                                                                              0  0   0  0  0  0  0  2BC 0    0  0  8BC                                                                              0                  (trifluoromethyl)-1H-                                                                         1.0                                                                              0  0   0  0  0  0  0  10D 0    7BC                                                                              8BC                                                                              10D                                                                              8BC                imidazo(4,5-6)pyridine                                                                        2.0                                                                              2SC                                                                              0   6BC                                                                              5BC                                                                              0  3SC                                                                              9BC                                                                              10D 10D  9BC                                                                              10D                                                                              10D                                                                              9BC                1-Benzyloxy-6-chloro-2-                                                                       0.5                                                                              0  0   0  0  0  0  0  0   0    0  0  4BC                                                                              0                  (trifluoromethyl)-1H-                                                                         1.0                                                                              0  0   0  0  0  0  0  2SC --   -- 5SC                                                                              3BC                                                                              4BC                imidazo(4,5-b)pyridine                                                                        2.0                                                                              0  0   0  0  0  0  0  5BC 0    3SC                                                                              3SB                                                                              3BC                                                                              4BC                1-Allyloxy-6-chloro-2-                                                                        0.5                                                                              0  0   0  0  0  0  0  9BC 0    4BC                                                                              0  6BC                                                                              3BC                (trifluoromethyl)-1H-                                                                         1.0                                                                              0  0   0  0  0  0  0  10D 0    8BC                                                                              7BC                                                                              9BC                                                                              8BC                imidazo(4,5-b)pyridine                                                                        2.0                                                                              0  0   0  3BC                                                                              0  0  4BC                                                                              10D 5BC  8.5                                                                              9.5BC                                                                            9BC                                                                              9BC                                                                  BC                          1-Isopropoxy-6-chloro-2-                                                                      0.5                                                                              0  0   0  0  0  0  0  8BC 2C   2BC                                                                              0  6BC                                                                              0                  (trifluoromethyl)-1H-                                                                         1.0                                                                              0  0   0  0  0  0  0  10D 2C   2BC                                                                              2S 9BC                                                                              4BC                imidazo(4,5-b)pyridine                                                                        2.0                                                                              2SC                                                                              0   0  0  0  0  0  10D --   6BC                                                                              8.5                                                                              9.5                                                                              9BC                                                                     BC BC                    1-(Allylcarbamoyloxy-                                                                         0.5                                                                              0  0   0  0  0  0  0  8BC 4BC  0  2S 6BC                                                                              0                  6-chloro-2-(trifluoro-                                                                        1.0                                                                              0  0   0  2BC                                                                              0  0  0  10D 10D  2BC                                                                              4BC                                                                              8BC                                                                              6BC                methyl)-1H-imidazo-                                                                           2.0                                                                              0  5BC 5BC                                                                              6BC                                                                              2C 2SC                                                                              5BC                                                                              10D 10D  5BC                                                                              8BC                                                                              10D                                                                              8BC                (4,5-b)pyridine                                                               1-Octanoyloxy-6-chloro-                                                                       0.5                                                                              0  0   0  0  0  0  0  7BC --   0  0  5BC                                                                              0                  2-(trifluoromethyl)-1H-                                                                       1.0                                                                              0  3C  5BC                                                                              3SB                                                                              0  0  2C 10D --   4BC                                                                              4BS                                                                              9BC                                                                              6BC                imidazo(4,5-b)pyridine                                                                        2.0                                                                              3SC                                                                              7BC 7BC                                                                              5BC                                                                              0  4SC                                                                              7BC                                                                              10D 10D  9BC                                                                              8BC                                                                              9.5BC                                                                            7BC                1-(2-Methoxy-3,6-dichloro-                                                                    0.5                                                                              0  3F  7F 6F 6F 0  8F 7F  10D  2F 2S 8F 5FS                benzoyloxy)-6-chloro-2-                                                                       1.0                                                                              2S 5F  10D                                                                              8F 10D                                                                              0  10D                                                                              8F  --   8F 3SF                                                                              10D                                                                              4FS                (trifluoromethyl)-1H-                                                                         2.0                                                                              4S 9F  10D                                                                              9F 9F 1S 10D                                                                              10D 10D  10D                                                                              4SF                                                                              10D                                                                              5FS                imidazo(4,5-b)pyridine                                                        1-(Methylcarbamoyloxy)-6-                                                                     0.5                                                                              0  0   0  0  0  0  0  10D --   4BC                                                                              2BC                                                                              9BC                                                                              5BC                chloro-2-(trifluoro-                                                                          1.0                                                                              2SC                                                                              3SC 4BC                                                                              4BC                                                                              0  1SC                                                                              3BC                                                                              10D 10D  7BC                                                                              8BC                                                                              10D                                                                              4BC                methyl)-1H-imidazo-                                                                           2.0                                                                              4SC                                                                              8BC 10D                                                                              6BC                                                                              0  5SC                                                                              10D                                                                              10D 10D  10D                                                                              10D                                                                              10D                                                                              10D                (4,5-b)pyridine                                                               1-Ethoxy-2,6-bis(trifluoro-                                                                   0.5                                                                              0  0   0  0  0  0  0  7BC --   0  0  0  0                  methyl)-1H-imidazo(4,5-b)-                                                                    1.0                                                                              0  0   0  0  0  0  0  10D --   2BC                                                                              0  7BC                                                                              2S                 pyridine        2.0                                                                              3SC                                                                              2SC 4BC                                                                              2BC                                                                              0  5SC                                                                              8BC                                                                              10D 10D  4BC                                                                              9BC                                                                              9BC                                                                              3S                 Control            0  0   0  0  0  0  0  0   0    0  0  0  0                  Control            0  0   0  0  0  0  0  0   0    0  0  0  0                  __________________________________________________________________________

EXAMPLE 88

1-Methoxy-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine wasevaluated under field conditions. The compound was formulated inconventional procedures and applied as a soil surface spray to bedsseeded with corn and selected weed species. The evaluations were carriedout in a sub-tropical climate; there having been no rainfall in thefirst seven days following application, 1/2 inch of sprinkler irrigationwas applied. Observations were made periodically for emergence, corninjury, and weed control. The results were as expressed in the followingtable, with date of observation expressed as the number of days from theday of seeding and compound application.

                                      TABLE IV                                    __________________________________________________________________________                                       Percent weed control                                       Emergence.sup.a                                                                         Crop Injury.sup.c                                                                      All Observations Day                       __________________________________________________________________________                                       17                                                      Rate                               Morn-   Black                              (Lbs./                                                                           Day Day                                                                              Day                                                                              Day                                                                              Day                                                                              Day                                                                              Prickly                                                                           Venice                                                                            Common                                                                             ing-                                                                              Foxtail                                                                           night-                                                                            Pig-              Compound     Acre)                                                                            5   7  11 11 17 38 sida                                                                              mallow                                                                            purslane                                                                           glory                                                                             millet                                                                            shade                                                                             weed              __________________________________________________________________________    1-methoxy-6-cchloro-2-                                                                     1  97  90 89 0.0                                                                              0.0                                                                              0.0                                                                              98  90  100  89  98  100 100               (trifluoromethyl)-1H-                                                         imidazo(4,5-b)pyridine                                                                     1.5                                                                              97  89 87 0.0                                                                              0.3                                                                              0.0                                                                              99  97  100  100 99  100 100                            2  72  94 95 0.0                                                                              0.7                                                                              0.0                                                                              99  96  100  91  99  100 100                            3   100+                                                                             100                                                                              98 0.3                                                                              2.3                                                                              1.7                                                                              100 100 100  96  100 100 100                            4  96  85 83 2.0                                                                              3.7                                                                              4.3                                                                              100 100 100  100 100 100 100               Control      0  100 100                                                                              100                                                                              0.0                                                                              0.0                                                                              0.0                                                                               0    0  0    0   0   0                                    (72).sup.b                                                                        (108)                                                                            (109)       (14.6).sup.d                                                                      (5.6)                                                                             (3.8)                                                                              (5) (24.5)                                                                            (2.6)                                                                             (4.1)             __________________________________________________________________________     .sup.a Emergence expressed as a percent of the control.                       .sup.b Number of emerged corn seedlings per 15 feet of row.                   .sup.c Crop injury on a 0-10 scale where 0 = no injury, 1-3 = slight, 4-6     = moderate, 7-9 = severe, and 10 - death of all plants.                       .sup.d Weeds/sq.ft. based on 5 one sq. ft. counts per plot.              

As noted above, the compounds of the present invention can be used inconjunction with other agricultural materials, including otherherbicides. Thus, in one embodiment, the present invention is directedto a method which comprises applying essentially simultaneously to aplant part an amount of a first substance which is:

1-methoxy-6-chloro-2-trifluoromethyl-1H-imidazo(4,5-b)pyridine,

1-methoxy-5-chloro-2-trifluoromethyl-1H-imidazo(4,5-b)pyridine, or

1-methoxy-2,6-bis(trifluoromethyl)-1H-imidazo(4,5-b)pyridine;

and an amount of a second substance which is:

alachlor,

atrazine,

butylate,

2-chloro-4-(1-cyano-1-methylethylamino)-6-ethylamino-s-triazine,

dalapon,

dinoseb,

diuron,

Eptc,

linuron,

oryzalin,

propachlor,

prapazine,

simazine,

trifluralin, or

Tca,

the amounts being such as to effect, in combination, growth inhibition.This embodiment of the present invention also comprehends a combinationof the first and second substances, which combination is useful inimplementing the method.

The substances serving as the second substance of the present herbicidalmethods and combinations are in every instance known compounds. For aconvenient compilation of information and references on these and otherknown herbicides, attention is directed to the Herbicide Handbook of theWeed Society of America, sec. ed., published by The W. F. HumphreyPress, Inc., Geneva, New York, 1970, and available from Weed ScienceSociety of America, Department of Agronomy, University of Illinois,Urbana, Ill. 61801.

The known herbicides serving as the second substance are generallycrystalline solids, typically white in color; the exceptions arebutylate (an amber liquid); EPTC (a light yellow-colored liquid); anddinoseb (which may exist as either a dark brown solid or a dark orangeliquid, depending on temperature). Each of these compounds isindividually effective at a range of rates, depending upon theparticular substance, the particular use (for example, whether aselective or general herbicidal effect is sought), and the type of soiland other growing conditions. The generally established rate ranges forthese known herbicides, when used individually, are as follows:

    ______________________________________                                                          Established Rate                                            Compound          in Lbs./Acre                                                ______________________________________                                        alachlor          1-4                                                         atrazine          2-4                                                         butylate          3-4                                                         2-chloro-4-(1-cyano-1-methyl-                                                  ethylamino)-6-ethylamino-                                                     s-triazine       1-4                                                         dalapon           .75-20                                                      dinoseb           .75-12                                                      diuron            0.6-6.4 (selective)                                                            4-16 (general)                                             EPTC              2-6                                                         linuron           0.5-3 (selective)                                                             1-3 (non crop)                                              oryzalin          1-4                                                         propachlor        3-6                                                         propazine         1-4                                                         simazine          2-4                                                         trifluralin       0.5-2                                                       TCA                4-30 (selective)                                                              50-200 (general)                                           ______________________________________                                    

In employing these known herbicides in combination with the herbicidesof the present invention, the precise ratio of the herbicidal agents toone another is not critical. It is generally preferred that the knownherbicide be used in an amount within its established rate range forindividual use as sole herbicidal agent, although because of theherbicidal effect attributable to the ether, lesser amounts within theestablished rate range or amounts below the established rate range areappropriate. Thus, amounts below the median of the established raterange generally give good results in combination with the specifiedethers. However, each of the ether and known herbicide components shouldbe employed in an amount which, if employed individually as soleherbicidal agent, would exert at least a minimal plant-growth inhibitingeffect. In the case of alachlor, atrazine, and propachlor, for example,the established rate ranges are 1-4 lbs./acre of alachlor, 2-4 lbs./acreof atrazine, or 3- 6 lbs./acre of propachlor; but good results generallyare obtained in the present combinations at application rates of 2.5lbs./acre or less of alachlor, 3 lbs./acre or less of atrazine, or 4.5lbs./acre or less of propachlor. For the specified ethers serving as thefirst component, application rates of 0.25-4 lbs./acre are desirable forselective activity, and preferred rates for selective activity aregenerally 1-2.5 lbs./acre.

The substances can be administered separately, although preferablyessentially simultaneously, and this mode of administration is sometimespreferred. Thus, for example, different herbicides may require differentmodes of applications which preclude a single application. Inparticular, each of butylate and EPTC is preferably applied to cornprior to planting and with mechanical mixing into the soil. The ethersof the present invention are preferably applied to corn immediatelyafter seeding but without mechanical mixing. Thus, separateadministration is sometimes preferred in order to make best utilizationof the respective herbicidal properties. Where separate administrationis preferred, the exact interval between applications is not critical;but optimal results generally are obtained when the respectiveadministrations are essentially simultaneously, such as within severalminutes to not more than within several hours of one another. The timeinterval between applications is largely dictated by the practicalitiesof agricultural practices.

Generally, however, it is preferred that both substances be formulatedas a single formulation. The formulation is conducted in accordance withconventional procedures, utilizing such adjuvants as surface-activeagents, inert finely-divided solids, and the like. Reference is made tothe discussion hereinabove concerning formulation of the compounds ofthe present invention, generally. Where the objective is selectiveherbicidal activity, it is generally preferred that the specified ethercomprise at least 40 percent by weight of the total herbicidally-activecomponent.

EXAMPLES 89-103

1-Methoxy-6-chloro-2-trifluoromethyl-1H-imidazo(4,5-b)pyridine wasevaluated in combination with each of a number of known herbicides. Theevaluation was conducted in each case in accordance with the standardscreening procedures described in preceding examples, each of theherbicides being applied separately but within rapid succession (withinan interval of not longer than about 5 minutes).

The results observed were as set forth in the following tables.

                                      TABLE V:                                    __________________________________________________________________________    COMBINATION OF 1-METHOXY-6-CHLORO-2-TRIFLUOROMETHYL-                          1H-IMIDAZO(4,5-b)PYRIDINE ("A") WITH ALACHLOR ("B")                           __________________________________________________________________________        Rates                                                                              Morn-         Barn-                                                                             Large                                              Com-                                                                              Lbs./                                                                              ing    Foxtail                                                                           Rag                                                                              yard                                                                              Crab-                                                                             Pig-       Velvet Jimson                                                                            Johnson                                                                            Lambs               pounds                                                                            Acre Glory                                                                             Corn                                                                             Millet                                                                            weed                                                                             Grass                                                                             grass                                                                             weed                                                                             Sorghum                                                                            Rice                                                                             Leaf                                                                              Corn                                                                             Weed                                                                              Grass                                                                              Quarter             __________________________________________________________________________    A + B                                                                             0.25 +                                                                             10D 0  10D 9SB                                                                              10N 9.5RS                                                                             9.5                                                                              3SB  9SR                                                                              4SB 0  6SB 9SB  9S                      0.05                       RS                                             "   0.25 + 1                                                                           10D 0  10D 9SR                                                                              10N 9.9RS                                                                             10N                                                                              5SB  10N                                                                              7SB 0  10D 10D  10N                 "   0.25 + 2                                                                           10D 1S 10D 9.5                                                                              10N 10N 10N                                                                              9SF  10N                                                                              9SB 0  9BS 10D  10N                                     RS                                                        "   0.25 + 4                                                                           10D 2S 10N 10D                                                                              10N 10N 10N                                                                              8SF  10N                                                                              9BS 2S 9BS 10D  10N                 "   0.5 +  0.5                                                                         10D 0  10D 10D                                                                              10N 9.5RS                                                                             9.5                                                                              3SB  8S 8SB 1S 8BS 9BS  10N                                                RS                                             "   0.5 + 1                                                                            10D 0  10N 10D                                                                              10N 10D 9.5                                                                              4BSF 8RS                                                                              8BSR                                                                              0  8BS 9.5BS                                                                              10N                                                RS                                             "   0.5 + 2                                                                            10D 3S 10D 9.5                                                                              10N 10N 10D                                                                              8SF  10N                                                                              9BS 0  9BS 9.5BS                                                                              9RS                                     BSR                                                       "   0.5 + 4                                                                            10D 3S 10N 10N                                                                              10N 10N 10N                                                                              9FSR 9.8RS                                                                            9.5BS                                                                             2S 9.5BS                                                                             10N  10N                                                        RS                                     "   1 + 0.5                                                                            10D 2SB                                                                              10D 10D                                                                              10N 9.5BS                                                                             9.5RS                                                                            7BS  8BSR                                                                             9BS 0  9BS 7BS  9RS                                                RS                                             "   1 + 1                                                                              10D 1S 10D 10D                                                                              10N 9.8RS                                                                             9.8RS                                                                            8BS  9RS                                                                              10D 3S 9BS 10D  10N                                                RS                                             "   1 + 2                                                                              10D 3S 10N 9.8                                                                              10N 9.8RS                                                                             10N                                                                              8BSF 9.5                                                                              10D 0  9.5BS                                                                             10D  10N                                     RSB                RS                                     "   1 + 4                                                                              10D 3S 10D 9.5                                                                              10N 10D 10N                                                                              9BSF 9.5                                                                              9SB 2S 9.5BS                                                                             10D  10N                                     BSR                RS                                     "   2 + 0.5                                                                            10D 3S 10D 8S 10N 9.8RS                                                                             9.5                                                                              9.5BS                                                                              7SB                                                                              10D 3S 9.5BS                                                                             9BS  9.8RS                                              RS                                             "   2 + 1                                                                              10D 1S 10D 9.5                                                                              10N 10N 9.8                                                                              9    9RS                                                                              8BS 1S 9.8BS                                                                             9BS  10N                                     RS         RS                                             "     2 + 2                                                                            10D 0  10D 9.8                                                                              10N 10N 10N                                                                              9BS  10D                                                                              9.5BS                                                                             1SB                                                                              9.5BS                                                                             10D  10N                                     RS                                                        "     2 + 4                                                                            10D 3S 10D 10D                                                                              10N 10N 10N                                                                              9.5BSF                                                                             10N                                                                              9.5BS                                                                             4SB                                                                              9.8BS                                                                             10D  10N                 Con-                                                                                0  0   0  0   0  0   0   0  0    0  0   0  0   0    0                   trol                                                                          __________________________________________________________________________

                                      TABLE VI:                                   __________________________________________________________________________    COMBINATION OF 1-METHOXY-6-CHLORO-2-TRIFLUOROMETHYL-1H-                       -IMIDAZO(4,5-b)PYRIDINE ("A") WITH ATRAZINE ("B")                             __________________________________________________________________________         Rates                                                                             Morn-               Lambs   Barn-  Large          John-              Lbs./                                                                              ing Pig-                                                                              Rag-     Velvet                                                                           Quat-                                                                             Jimson                                                                            yard    Crab-  Foxtail                                                                          Sor-                                                                              son                    pounds                                                                             Acre                                                                              Glory                                                                             weed                                                                              weed Corn                                                                             Leaf                                                                              er  Weed                                                                              Grass                                                                             Rice                                                                             grass                                                                             Corn                                                                             Millet                                                                            ghum                                                                              Grass              __________________________________________________________________________    A + B                                                                              1/4                                                                             1/4                                                                             8SD 9RS 8RS  0  3BS 7RS 8.5SD                                                                             5BS 2BS                                                                              4S  0  3S  0   2S                 "    1/4                                                                             1/2                                                                             10D 9.5RS                                                                             8RSD 0  5BS 7RSD                                                                              9SD 8SD 3BS                                                                              4S  0  4BS 0   2S                 "    1/4                                                                             1 9.5SD                                                                             10N 8RSD 0  7SD 7RS 9SD 9.5SD                                                                             3BS                                                                              6S  0  4BS 0   4BS                "    1/4                                                                             2 10D 9.5RS                                                                             9.5RSD                                                                             0  9.5 SD                                                                            7RS 9.5SD                                                                             9.5SD                                                                             3BS                                                                              8S  0  7SD 0   4BS                "    1/2                                                                             1/4                                                                             10D 9.5RS                                                                             6.5SD                                                                              0  7SD 7.5RS                                                                             9SD 9SD 3BS                                                                              7RS 0  8SD 0   4BS                "    1/2                                                                             1/2                                                                             10D 9RS 9SD  0  7SD 5RS 9.5SD                                                                             9.5SD                                                                             4BS                                                                              7RS 0  7SD 0   7SD                "    1/2                                                                             1 10D 9.5RS                                                                             9.5RSD                                                                             1S 6SD 6.5RS                                                                             9SD 9SD 3BS                                                                              8SD 0  8.5SD                                                                             0   6.5SD              "    1/2                                                                             2 10D 9RS 9.5RSD                                                                             0  9SD 7RS 8.5SD                                                                             10D 3BS                                                                              9SD 0  9.5SD                                                                             0   6.5SD              "    1 1/4                                                                             10D 9RS 9SD  0  6.5SD                                                                             7RS 9SD 9.5SD                                                                             3BS                                                                              9.5SD                                                                             0  10D 3BS 7SD                "    1 1/2                                                                             10D 9.5RS                                                                             9.5SD                                                                              0  9SD 7RS 9.5SD                                                                             9.5SD                                                                             2BS                                                                              9.5SD                                                                             0  10D 4BS 8SD                "    1 1 10D 9.5RS                                                                             10D  0  9SD 8RS 9.5SD                                                                             10D 3BS                                                                              9.5SD                                                                             0  10D 4BS 7SD                "    1 2 10D 9.5RS                                                                             10D  0  9SD 7RSD                                                                              9.5SD                                                                             10D 3BS                                                                              9.5SD                                                                             0  10D 3BS 9SD                "    2 1/4                                                                             10D 9.5RS                                                                             9SD  1S 9.5SD                                                                             7RS 9.5SD                                                                             10D 3BS                                                                              9.5SD                                                                             0  10D 7SD 9.5SD              "    2 1/2                                                                             10D 9.5RS                                                                             10D  0  9.5SD                                                                             7.5RS                                                                             9.5SD                                                                             9.5SD                                                                             4BS                                                                              10D 0  10D 8SD 9SD                "    2 1 10D 9.5RS                                                                             10D  2S 10D 8RS 9.5SD                                                                             9.5SD                                                                             5BS                                                                              9.5SD                                                                             1S 10D 8SD 9SD                "    2 2 10D 9.5RS                                                                             10D  2S 10D 8RS 10D 10D 4BS                                                                              9.5SD                                                                             0  10D 7SD 9SD                Control                                                                            --                                                                              --                                                                              0   0   0    0  0   0   0   0   0  0   0  0   0   0                  Control                                                                            --                                                                              --                                                                              0   0   0    0  0   0   0   0   0  0   0  0   0   0                  Control                                                                            --                                                                              --                                                                              0   0   0    0  0   0   0   0   0  0   0  0   0   0                  __________________________________________________________________________

                                      TABLE VII:                                  __________________________________________________________________________    COMBINATION OF 1-METHOXY-6-CHLORO-2-TRIFLUOROMETHYL-                          1H-IMIDAZO(4,5-b)PYRIDINE ("A") WITH BUTYLATE ("B")                           __________________________________________________________________________         Rates Morn-          Barn-                                                                             Large         Vel-       John-                                                                             Lambs              Com- Lbs./ ing    Foxtail                                                                           Rag-                                                                              yard                                                                              Crab-                                                                             Pig Sor-  vet    Jimson                                                                            son Quart-             pounds                                                                             Acre  Glory                                                                             Corn                                                                             Millet                                                                            weed                                                                              Grass                                                                             grass                                                                             weed                                                                              ghum                                                                              Rice                                                                            Leaf                                                                              Corn                                                                             Weed                                                                              Grass                                                                             er                 __________________________________________________________________________    A + B                                                                              0.25 + 1.0                                                                          10D 0  7SF 5SB 3S  4SB 9.5BS                                                                             9SF 0  10D                                                                             0   4SB 9SR 10D                "    0.25 + 2.0                                                                          6SB 0  9SF 6SB 8S  6SB 9BS 10D 3S 10D                                                                             0   6SB 9.5RS                                                                             10D                "    0.25 + 3.0                                                                          10D 0  9SBF                                                                              4SB 8SB 10D 9BSR                                                                              10D 7S 10D                                                                             0   7SB 10D 10D                "    0.25 + 4.0                                                                          10D 0  9SB 8SB 8SB 10D 10D 10D 9SB                                                                              10D                                                                             0   7SB 10D 10D                "    0.5 + 1.0                                                                           10D 1S 6SB 9.5BS                                                                             7SB 5SB 8BS 9SBF                                                                              3S 10D                                                                             2S  9BS 9RSB                                                                              10D                "    0.5 + 2.0                                                                           9BS 1S 8BS 10D 8SB 9.5RS                                                                             10D 10D 6S 10D                                                                             1S  8BS 9RS 10D                "    0.5 + 3.0                                                                           10D 3S 9.5BS                                                                             9.5RS                                                                             10D 10D 10D 10D 9.5S                                                                             10D                                                                             1S  9BS 10D 10D                "    0.5 + 4.0                                                                           10D 4S 9.5BSR                                                                            9.5BSR                                                                            10D 10D 10D 10D 9.5S                                                                             10D                                                                             3S  9BS 10D 10D                "    1.0 + 1.0                                                                           10D 5S 10D 10D 9.5BS                                                                             9BS 9.5BS                                                                             9.5BS                                                                             3B 10D                                                                             4S  9BS 9BS 10D                "    1.0 + 2.0                                                                           10D 5S 10D 10D 9.5BS                                                                             10D 10D 10D 8S 10D                                                                             4S  9BS 10D 10D                "    1.0 + 3.0                                                                           10D 4S 10D 10D 8BS 8BS 9BS 10D 5S 10D                                                                             3S  7BS 9.5BS                                                                             10D                "    1.0 + 4.0                                                                           10D 3S 10D 10D 9.5BSR                                                                            9.5BS                                                                             9.5FS                                                                             9SF 7S 10D                                                                             3S  9BS 10D 10D                "    2.0 + 1.0                                                                           10D 5S 10D 10D 9.5BS                                                                             9BS 9BS 8BSF                                                                              3B 10D                                                                             5SB 8SB 9BS 10D                "    2.0 + 2.0                                                                           10D 5S 10D 10D 9.5BS                                                                             10D 8S  9.5BSF                                                                            5S 10D                                                                             6SB 8BS 9BSR                                                                              9SB                "    2.0 + 3.0                                                                           10D 6SB                                                                              10D 10D 10D 9.5BS                                                                             9.5SB                                                                             10D 8S 10D                                                                             5S  8BS 9.5RS                                                                             10D                "    2.0 + 4.0                                                                           10D 6SB                                                                              10D 10D 10D 10D 9.5BS                                                                             10D 9S 10D                                                                             6SB 9BS 10D 10D                Control                                                                            0     0   0  0   0   0   0   0   0   0  0 0   0   0   0                  __________________________________________________________________________

                                      TABLE VIII:                                 __________________________________________________________________________    COMBINATION OF 1-METHOXY-6-CHLORO-2-TRIFLUOROMETHYL-1H-                       IMIDAZO(4,5-b)PYRIDINE ("A") WITH 2-CHLORO-4-(1-CYANO-                        1-METHYLETHYLAMINO)-6-ETHYLAMINO-s-TRIAZINE ("B")                             __________________________________________________________________________         Rates Morn-          Barn-                                                                             Large          Vel-      John-                                                                             Lambs              Com- Lbs./ ing    Foxtail                                                                           Rag-                                                                              yard                                                                              Crab-                                                                             Pig-                                                                              Sor-   vet   Jimson                                                                            son Quart-             pounds                                                                             Acre  Glory                                                                             Corn                                                                             Millet                                                                            weed                                                                              Grass                                                                             grass                                                                             weed                                                                              ghum                                                                              Rice                                                                             Leaf                                                                             Corn                                                                             Weed                                                                              Grass                                                                             er                 __________________________________________________________________________    A + B                                                                              0.25 + 0.25                                                                         10D 0  10D 10D 4SB 6SB 5S  3SB 4S 9BS                                                                              2S 9BS 7BS 8SB                "    0.25 + 0.5                                                                          10D 3S 10D 10D 7SB 9.5BS                                                                             7S  8BS 9BS                                                                              9.5BS                                                                            2S 9.5BS                                                                             9.5BS                                                                             8SB                "    0.25 + 1.0                                                                          10D 4S 10D 10D 9.5BS                                                                             10D 7SB 6SB 8BS                                                                              10D                                                                              3S 10D 10D 9.5BS              "    0.25 + 2.0                                                                          10D 5S 10D 10D 10D 10D 10D 9.5BS                                                                             10D                                                                              10D                                                                              4SB                                                                              9.5BS                                                                             9.5BS                                                                             9.5BS              "    0.5   + 0.25                                                                        10D 3S 10D 10D 8SB 7SB 6SB 6SB 8B 9BS                                                                              3S 9BS 9.5BS                                                                             8S                 "    0.5 + 0.5                                                                           10D 2S 10D 10D 8SB 9.5SB                                                                             6SB 6SB 8B 10D                                                                              2S 9BS 9.5BS                                                                             9SB                "    0.5 + 1.0                                                                           10D 2SB                                                                              10D 10D 9.5SB                                                                             10D 9.5BS                                                                             9.5BS                                                                             10D                                                                              9.8BS                                                                            2SB                                                                              9.5BS                                                                             9BS 9SB                "    0.5 + 2.0                                                                           10D 3SB                                                                              10D 10D 9.5BS                                                                             10D 9.5BS                                                                             9.8BS                                                                             10D                                                                              10D                                                                              2S 9.5BS                                                                             10D 9.5SB              "    1.0  + 0.25                                                                         9.5BS                                                                             2S 10D 10D 9.5BS                                                                             10D 8SB 7SB 7B 9.5BS                                                                            2S 9.5BS                                                                             9.5BS                                                                             9SB                "    1.0 + 0.5                                                                           10D 2SB                                                                              10D 10D 9.5BS                                                                             10D 9.5BS                                                                             9.5BS                                                                             10D                                                                              10D                                                                              2S 9.5BS                                                                             10D 9S                 "    1.0 + 1.0                                                                           10D 2SB                                                                              10D 10D 9.5BS                                                                             9.8BS                                                                             9.5SB                                                                             9.5BS                                                                             10D                                                                              10D                                                                              2S 10D 9.5BS                                                                             9.5SB              "    1.0 + 2.0                                                                           10D 4SB                                                                              10D 10D 9.5BS                                                                             10D 9.5BS                                                                             10D 10D                                                                              9.8BS                                                                            3S 9.5BS                                                                             10D 9SB                "    2.0  + 0.25                                                                         10D 2S 10D 10D 9.5BS                                                                             9.5BS                                                                             9.5BS                                                                             8SB 7BS                                                                              9.5BS                                                                            3S 9.5BS                                                                             9.5BS                                                                             9SB                "    2.0 + 0.5                                                                           10D 5SB                                                                              10D 10D 10D 10D 9.5BS                                                                             9.5BS                                                                             10D                                                                              10D                                                                              5SB                                                                              9.5BS                                                                             10D 10D                "    2.0 + 1.0                                                                           10D 4SB                                                                              10D 10D 10D 10D 9.8BS                                                                             10D 10D                                                                              10D                                                                              3SB                                                                              10D 10D 9SB                "    2.0 + 2.0                                                                           10D 4SB                                                                              10D 10D 10D 10D 9.5BS                                                                             10D 10D                                                                              10D                                                                              5SB                                                                              10D 10D 10D                Control                                                                            0     0   0  0   0   0   0   0   0   0  0  0  0   0   0                  __________________________________________________________________________

                                      TABLE IX:                                   __________________________________________________________________________    COMBINATION OF 1-METHOXY-6-CHLORO-2-TRIFLUOROMETHYL-                          1H-IMIDAZO(4,5-b)PYRIDINE ("A") WITH DALAPRON ("B")                           __________________________________________________________________________         Rates Morn-          Barn-                                                                             Large          Vel-      John-                                                                             Lambs              Com- Lbs./ ing    Foxtail                                                                           Rag yard                                                                              Crab-                                                                             Pig-                                                                              Sor-   vet   Jimson                                                                            son Quart-             pounds                                                                             Acre  Glory                                                                             Corn                                                                             Millet                                                                            weed                                                                              Grass                                                                             grass                                                                             weed                                                                              ghum                                                                              Rice                                                                             Leaf                                                                             Corn                                                                             Weed                                                                              Grass                                                                             er                 __________________________________________________________________________    A + B                                                                              0.25 + 0.75                                                                         3SBC                                                                              0  4SB 3S  0   2S  4S  0   0  3SB                                                                              0  0   0   0                  "    0.25 + 1.5                                                                          2B  0  6BS 10D 0   0   4B  0   2S 3S 0  0   0   0                  "    0.25 + 3.0                                                                          2B  0  9BS 10D 0   7SB 3BS 0   6SB                                                                              4S 0  4B  0   3S                 "    0.25 + 6.0                                                                          3SB 0  10D 9BS 3BS 8BS 4BS 3BS 5SB                                                                              3SB                                                                              0  4BS 0   --                 "     0.5 + 0.75                                                                         6SB 0  8BSR                                                                              10D 2S  5SB 5SB 0   0  4S 0  7BS 3S  7SR                "    0.5 + 1.5                                                                           9BS 0  9BS 10D 4BS 8BS 3B  1S  3S 6SB                                                                              0  8BS 0   6RS                "    0.5 + 3.0                                                                           9BS 1S 10D 10D 5SB 7SB 3B  1S  5SB                                                                              7SB                                                                              0  6BS 2S  7RS                "    0.5 + 6.0                                                                           10D 0  10D 9.5BS                                                                             7BS 8BS 10D 3SB 7BS                                                                              7SB                                                                              0  8BS 2S  7RS                "     1.0 + 0.75                                                                         9.5BS                                                                             0  10D 10D 6BS 10D 6BS 3SB 5BS                                                                              9.5BS                                                                            0  10D 4S  6SR                "    1.0 + 1.5                                                                           9.5BS                                                                             0  10D 10D 4SB 9BS 7BS 2SB 4B 10D                                                                              0  10D 3SB 7SR                "    1.0 + 3.0                                                                           10D 0  10D 10D 5BS 9.5BS                                                                             9BS 3SB 5BS                                                                              10D                                                                              0  10D 6BS 7RS                "    1.0 + 6.0                                                                           10D 4F 10D 10D 7BSR                                                                              10D 10D 6BSF                                                                              9BS                                                                              10D                                                                              4FS                                                                              10D 4SB 8S                 "     2.0 + 0.75                                                                         10D 0  10D 10D 4BS 7BS 9BS 8BS 6BS                                                                              9.5BS                                                                            2S 10D 8BS 10D                "    2.0 + 1.5                                                                           10D 3S 10D 10D 9BS 10D 9BS 8BS 9BS                                                                              10D                                                                              3S 10D 7BS 10D                "    2.0 + 3.0                                                                           10D 1S 10D 10D 9BS 10D 10D 9BS 9BS                                                                              10D                                                                              2S 10D 7BS 9RS                "    2.0 + 5.0                                                                           10D 2S 10D 10D 9.5BS                                                                             10D 10D 6BS 8BS                                                                              10D                                                                              4SB                                                                              9.5BS                                                                             8BS 9RS                Control                                                                            0     0   0  0   0   0   0   0   0   0  0  0  0   0   0                  __________________________________________________________________________

                                      TABLE X:                                    __________________________________________________________________________    COMBINATION OF 1-METHOXY-6-CHLORO-2-TRIFLUOROMETHYL-                          1H-IMIDAZO(4,5-b)PYRIDINE ("A") WITH DINOSEB ("B")                            __________________________________________________________________________                     Fox-                                                             Rates Morn-  tail    Barn-                                                                             Large          Vel-   Jim-                                                                              John-                                                                             Lambs              Com-                                                                              Lbs./ ing    mil-                                                                              Rag-                                                                              yard                                                                              Crab-                                                                             Pig-                                                                             Sorg-   vet    son son Quart-             pounds                                                                            Acre  Glory                                                                             Corn                                                                             let weed                                                                              Grass                                                                             grass                                                                             weed                                                                             hum Rice                                                                              Leaf                                                                              Corn                                                                             Weed                                                                              Grass                                                                             er                 __________________________________________________________________________    A + B                                                                             0.25 + 1.0                                                                          2B  0  0   7SB 0   2S  2S 0   0   3SB 0  7SB 2S  5S                 "   0.25 + 2.0                                                                          5SB 0  2S  10D 0   0   2S 0   0   3SB 0  8BS 0   5S                 "   0.25 + 4.0                                                                          9BS 0  2S  10D 2S  2S  6S 0   0   3S  0  9BS 0   5S                 "   0.25 + 8.0                                                                          9BS 0  4S  10D 4SR 5RS 8SR                                                                              2S  3S  3S  1S 10D 2S  6S                 "   0.5 + 1.0                                                                           6SB 0  3SB 10D 5SB 8BS 8SR                                                                              2S  3BS 5SB 0  9.5BS                                                                             2S  7S                 "   0.5 + 2.0                                                                           10D 0  8BS 10D 4SB 6SB 9SR                                                                              1SB 1B  5SB 0  9.5BS                                                                             3SB 9SR                "   0.5 + 4.0                                                                           10D 0  7SB 10D 4SB 8BSR                                                                              7SR                                                                              2SB 2SB 6SB 0  9.5BS                                                                             2SB 7SR                "   0.5 + 8.0                                                                           10D 2S 7SB 10D 7SR 7SRB                                                                              6SR                                                                              3S  2SB 5SB 0  10D 2S  9SR                "   1.0 + 1.0                                                                           10D 2S 10D 10D 9SB 9.5RS                                                                             10N                                                                              7BS 10D 10D 1S 9.5BS                                                                             8BS 10D                "   1.0 + 2.0                                                                           10D 1S 10D 10D 9BS 10D 10D                                                                              8BS 4BS 7BS 1S 10D 6BS 10D                "   1.0 + 4.0                                                                           10D 2SB                                                                              10D 10D 8BS 10D 10D                                                                              6BS 4BS 8BS 0  10D 7BS 10D                "   10 + 8.0                                                                            10D 1S 7BS 10D 7BS 10D 9.5RS                                                                            4BS 6SB 10D 0  10D 6BS 10D                "   2.0 + 1.0                                                                           10D 4SB                                                                              10D 10D 10D 10D 9SB                                                                              9BS 8BS 10D 4SB                                                                              10D 10D 10D                "   2.0 + 2.0                                                                           10D 3S 10D 10D 10D 10D 10D                                                                              10D 8BS 10D 4SB                                                                              10D 9.5BS                                                                             10D                "   2.0 + 4.0                                                                           10D 2S 10D 10D 9.5BS                                                                             10D 10D                                                                              9BS 8BS 10D 1S 10D 9.5BS                                                                             10D                "   2.0 + 8.0                                                                           10D 3SB                                                                              10D 10D 10D 10D 10D                                                                              8BS 8BSC                                                                              10D 2S 10D 10D 10D                Control                                                                           0     0   0  0   0   0   0   0  0   0   0   0  0   0   0                  __________________________________________________________________________

                                      TABLE XI:                                   __________________________________________________________________________    COMBINATION OF 1-METHOXY-6-CHLORO-2-TRIFLUOROMETHYL-                          1H-IMIDAZO(4,5-b)PYRIDINE ("A") WITH DIURON ("B")                             __________________________________________________________________________                     Fox-                                                             Rates Morn-  tail    Barn-                                                                             Large          Vel-   Jim-                                                                              John-                                                                             Lambs              Com-                                                                              Lbs./ ing    mil-                                                                              Rag-                                                                              yard                                                                              Crab-                                                                             Pig-                                                                             Sorg-   vet    son son Quart-             pounds                                                                            Acre  Glory                                                                             Corn                                                                             let weed                                                                              Grass                                                                             grass                                                                             weed                                                                             hum Rice                                                                              Leaf                                                                              Corn                                                                             Weed                                                                              Grass                                                                             er                 __________________________________________________________________________    A + B                                                                             0.25 + 0.25                                                                         10D 0  4SB 10D 4BS 5SB 8BS                                                                              1B  1B  5BS 0  7BS 2SB 8SR                "   0.25 + 0.5                                                                          6BSL                                                                              0  5BS 10D 9BS 8BS 9BS                                                                              2B  4B  8BS 0  9BS 3BS 9SR                "   0.25 + 1.0                                                                          10D 0  8BS 10D 10D 9BS 9BS                                                                              3BC 3B  10D 3S 9BS 8BS 9SR                "   0.25 + 2.0                                                                          10D 5BS                                                                              10D 10D 10D 9.5BS                                                                             9BS                                                                              4BS 7B  10D 5SB                                                                              9BS 9.5BS                                                                             10N                "0.5 + 0.25                                                                       10D   2B  8BS                                                                              10D 7BS 8BS 9.5RS                                                                             3SB                                                                              4B  9BS 0   9BS                                                                              7BS 9RS                    "   0.5 + 0.5                                                                           9BS 2SB                                                                              10D 9.5BS                                                                             9BS 8BS 9BS                                                                              2S  4B  9BS 0  9BS 9.5BS                                                                             9.5RS              "   0.5 + 1.0                                                                           10D 2S 10D 10D 10D 9BS 9.5BS                                                                            2SB 4B  10D 5SB                                                                              9.5BS                                                                             9.5BS                                                                             9RS                "   0.5 + 2.0                                                                           10D 5SB                                                                              10D 10D 10D 9BS 9BS                                                                              3CSB                                                                              5B  10D 4SB                                                                              9BS 9BS 9RS                "   1.0 + 0.25                                                                          9BS 2S 10D 10D 10D 9.5BS                                                                             9.5BS                                                                            3SB 4B  10D 2S 9.5BS                                                                             9.5BS                                                                             10N                "   1.0 + 0.5                                                                           10D 4SB                                                                              10D 10D 10D 9.5BS                                                                             9.5BS                                                                            7BS 9B  10D 4SB                                                                              10D 10D 9.5RS              "   1.0 + 1.0                                                                           10D 7SB                                                                              10D 10D 10D 9.5BS                                                                             9.5BS                                                                            10D 9B  10D 8BS                                                                              9BS 10D 9.5RS              "   1.0 + 2.0                                                                           10D 4SB                                                                              10D 10D 10D 9.5BS                                                                             9.5BS                                                                            10D 9.5B                                                                              10D 7BS                                                                              9.5BS                                                                             10D 9.5RS              "   2.0 + 0.25                                                                          10D 5SB                                                                              10D 10D 10D 9.5BS                                                                             10D                                                                              9BS 9B  10D 4SB                                                                              9.5BS                                                                             10D 10N                "   2.0 + 0.5                                                                           10D 7SB                                                                              10D 10D 10D 9.5BS                                                                             9.5BS                                                                            9.5B                                                                              9B  10D 6SB                                                                              9.5BS                                                                             10D 9.5RS              A + B                                                                             2.0 + 10D0                                                                              7SB                                                                              10D 10D 10D 9.5BS                                                                             10D                                                                              10D 9.5B                                                                              10D 6SB                                                                              9.5BS                                                                             10D 10N                "   2.0 + 2.0                                                                           10D 7SB                                                                              10D 10D 10D 9.5BS                                                                             10D                                                                              9B  9.5B                                                                              10D 8BS                                                                              9.5BS                                                                             10D 10N                Control                                                                           0     0   0  0   0   0   0   0  0   0   0   0  0   0   0                  __________________________________________________________________________

    TABLE XII      COMBINATION OF 1-METHOXY-6-CHLORO-2-TRIFLUOROMETHYL-  1H-IMIDAZO(4,5-b)P     YRIDINE ("A") WITH EPTC ("B")     Fox-             Rates Morn-  tail     Barn- Large Com- Lbs./ ing  Mil- Rag- yard Crab- Pig- Sor-  Velvet     Jimson Johnson Lambs pounds Acre Glory Corn let weed Grass grass weed     ghum Rice Leaf Corn Weed Grass Quarter       A + B 0.25 + 1.0 10D 3S 9BS 8SB 7BS 6BS 8SB 10D 8S 10D 0 8BS 10D 9.5RS     " 0.25 + 2.0 10D 2S 9BS 10D 9BSF 9.5RSB 10N 10D 10N 10D 4S 9BS 10D 10N "     0.25 + 3.0 10D 7FS 9.5BS 10D 9BSF 10D 10N 10D 9.8RS 10D 4S 10D 10N 10N "     0.25 + 4.0 10D 8FS 10D 10D 9BSF 10D 10N 10D 10N 10D 7FS 9BSR 10N 9.5RS "     0.5 + 1.0 10D 1S 10D 10D 8BS 7BS 10D 10D 8BSR 10N 4S 9BS 10D 10N " 0.5 +     2.0 10D 5SF 10D 10D 9.5NBSR 10D 10N 9.8RSF 9.5RS 10D 4S 9BS 10D 10N "     0.5 + 3.0 10D 7FS 10D 10D 9.5BSF 10D 10N 10D 10N 10D 6SF 9.5BS 10D 9.8RS     " 0.5 + 4.0 10D 8FS 10D 10D 9.8BS 10N 10N 10D 10N 10D 8FS 9BS 10D 10N "     1.0 + 1.0 10D 4S 10D 10D 9.8BS 9.5BS 9.5BSR 10D 8SB 9.5BS 4S 9.5BS 9.5BS     9RS " 1.0 + 2.0 10D 8SB 10D 10D 10D 10D 10N 10D 10D 10D 5S 9BS 10D 9.5RS     " 1.0 + 3.0 10D 7SBF 10D 10D 10D 10D 10D 10D 10N 10D 8BSF 9.5BS 10D     9.5RS " 1.0 + 4.0 10D 7SB 10D 10D 10D 10D 10N 10D 10D 10D 8SBF 10D 10D     9.8RS " 2.0 + 1.0 10D 7SB 10D 10D 10D 10D 9.5RSB 10D 8SB 10D 7SB 9BS 10D     9.5RS " 2.0 + 2.0 10D 8SB 10D 9SB 10D 10D 9.5RSB 10D 10D 10D 7SB 10D 10D     10N " 2.0 + 3.0 10D 10D 10D 10D 10D 10D 10N 10D 10N 9.8BSR 9SB 10D 10D     9.8RS " 2.0 + 4.0 10D 10D 10D 10N 10D 10D 10N 10D 10D 10D 9BS 9.5BS 10D     9.8RS Con- trol 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

    TABLE XIII      COMBINATION OF 1-METHOXY-6-CHLORO-2-TRIFLUOROMETHYL- 1H-IMIDAZO(4,5-b)PY     RIDINE ("A") WITH LINURON ("B")     Fox-             Rates Morn-  tail     Barn- Large Com- Lbs./ ing  Mil- Rag- yard crab- Pig- Sor-  Velvet     Jimson Johnson Lambs pounds Acres Glory Corn let weed Grass grass weed     ghum Rice Leaf Corn Weed Grass Quarter       A + B 0.25 + 0.25 2SBC 2SB 8BS 10D 4BS 5S 9SB 0 2B 9BS 0 8BS 2SB 9.5RS     " 0.25 + 0.5 3SB 0 8BS 7BS 8BS 5S 9SB 0 2B 10D 0 8BS 9BS 10D " 0.25 +     1.0 4SB 0 10D 9BS 10D 9BS 10D 3BS 4B 10D 0 9BS 9BS 9SR " 0.25 + 2.0 9BS     3S 10D 10D 9.5BS 9BS 9S 4SB 4B 10D 4BS 8BS 8BS 8SR " 0.5 + 0.25 10D 3B     8BS 9BS 8BS 7SB 9BS 3B 3B 9BS 1S 9BS 7BS 9SRB " 0.5 + 0.5 5SB 0 8BS 9BS     9BS 7BS 10D 2S 2B 10D 0 9BS 9BS 9SR " 0.5 + 1.0 9BS 0 10D 9BS 9BS 8BS 9S     3S 3B 10D 2S 8BS 8BS 9SR " 0.5 + 2.0 10D 3S 10D 10D 10D 9.5BS 9.5BS 3SB     4B 10D 3S 9BS 9.5BS 9SR " 1.0 + 0.25 10D 2S 10D 10D 9.5BS 9.5BS 9.5BS     4SB 3B 9.5BS 2S 9.5BS 9.5BS 9SR " 1.0 + 0.5 10D 3S 10D 10D 10D 9BS 9.5BS     8B 4B 10D 3S 9.5BS 10D 9.5RS " 1.0 + 1.0 10D 4SB 10D 10D 10D 9.5 BS     9.5BS 9BS 5B 10D 3S 9.5BS 9.5BS 9.5RS " 1.0 + 2.0 10D 6SB 10D 10D 10D     9.5BS 9.5BS 9.5BS 6B 10D 5SB 9.5BS 10D 10D " 2.0 + 0.25 10D 5S 10D 10D     10D 9.5BS 9.5BS 9.5BS 9B 10D 5SB 10D 10D 9.5RS " 2.0 + 0.5 10D 5SB 10D     10D 10D 9.5BS 9.5BS 9.5BS 8B 10D 7SB 9.5BS 9.5BS 9.5RS " 2.0 + 1.0 10D     6SB 10D 10D 10D 9.5BS 10D 9B 8B 10D 5SB 9.5BS 9.5BS 9.5RS " 2.0 + 2.0     10D 7SB 10D 10D 10D 9.5BS 9.5BS 10D 9BS 10D 6SB 10D 10D 9.5RS Con- trol     0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

    TABLE XIV      COMBINATION OF 1-METHOXY-6-CHLORO-2-TRIFLUOROMETHYL-  1H-IMIDAZO(4,5-b)P     YRIDINE ("A") WITH ORYZALIN ("B")             Fox-    Rates Morn-     Barn-  Large  tail Com- Lbs./ ing Pig- Rag-  Velvet Lambs Jimson yard     Crab-  Mil- Sor- Johnson pounds Acre Glory weed WeedCorn Rice grass corn     let ghum Grass       A + B 1/4 1/2 5S 6S 5S 6.5BS 5.5CS 10N 3CS 7RS 6.5CS 9.5RS 5CS 8.5SD     7BS 6.5BS " 1/4 1 5S 7.5RS 6.5CRS 7.5BS 6CS 9.5RS 6S 8.5RS 8CS 9.5RS 7BS     9SD 7.5BS 7BS " 1/4 2 9BSD 9RS 8RS 8BS 7CS 10N 6.5S 9RS 8CS 10N 8BS     9.5RS 8BPS 8BSD " 1/4 4 9.5BSD 9RS 8.5RS 9BS 9BS 10N 7BS 9.5RS 9BS 10N     9BS 10D 9BS 8.5BSD " 1/2 1/2 8BSD 8RS 8.5BSD 6BS 5CBS 9.5RS 5S 6.5RS     6.5CS 9RS 5BS 9BSD 6.5RS 7BSD " 1/2 1 9.5BSD 9.5RS 9BS 7BS 6.5BS 10N     9BSD 9RS 7.5BSC 10N 7BS 10D 7BS 8SD " 1/2 2 9.5BSD 9.5RS 9BSD 7BS 8.5BSD     10N 8BSD 9.5RS 8.5BS 10N 8BS 9.5SD 8.5BS 8BSD " 1/2 4 10D 9.5RS 9.5SD     8BS 8.5BSD 10N 9BSD 10D 8.5BS 10N 7.5BS 10N 9BS 8BSD " 1 1/2 10D 9RS     9.5SD 4S 6BSD 9.5RS 9.5BSD 9SD 7BS 9.5SD 4S 10D 7BS 9BSD " 1 1 10D 9RS     9.5SD 7BS 7BSD 10N 9.5BSD 9SD 7BS 9.5RS 6S 9SD 5BS 9.BSD " 1 2 9.5BSD     10N 9.5BSD 7BS 9.5BSD 10N 9BSD 10D 8BS 10N 7.5BS 10D 9SD 9.5SD " 1 4 10D     10N 10D 7BS 9.5BSD 10N 9.5BSD 10D 8.5BS 10N 8.5BS 10D 9BSD 9.5BSD " 2     1/2 10D 9.5RS 9.5SD 2.5BS 10D 10N 9.5SD 9.5RS 7SD 10N 3S 10D 7BS 10D "     21 10D 9.5SD 9.5SD 4BS 10D 9.5RS 9.5SD 10D 8BSD 10N 4.5BS 10D 7.5BSD 10D     " 2 2 10D 10N 9.5SD 6.5BS 10D 10N 10D 10D 8BSD 9.5SD 5.5S 10D 7.5BSD     9.5SD " 2 4 9.5SD 10D 10D 3.5S 9.5SD 10N 10D 10D 6.5BS 10N 5.5S 10D     8.5BSD 10D Con- trol -- -- 0 0 0 0 0 0 0 0 0 0 0 0 0 0

    TABLE XV      COMBINATION OF 1-METHOXY-6-CHLORO-2-TRIFLUOROMETHYl-  1H-IMIDAZO(4,5-b)P     YRIDINE ("A") WITH PROPACHLOR ("B")     Fox-             Rates Morn-     tail  Barn- Large Com- Lbs./ ing  Mil- Rag- yard Crab- Pig- Sor- Velvet     Jimson Johnson Lambs pounds Acre Glory Corn let weed Grass grass weed     ghum Rice Leaf Corn Weed Grass Quarter       A + B 0.25 + 1.0 7BS 0 10D 10D 9RS 8RS 10D 2B 9RS 6SB 0 10D 4SR 7RS "     0.25 + 2.0 10D 0 10D 10D 9RS 8RS 5SB 3SB 9RS 7BS 0 9BS 3S 6RS " 0.25 +     3.0 9BS 0 10D 10D 9RS 10D 10D 4S 10N 9BSR 0 9BS 4S 7S " 0.25 + 4.0 10D     1S 10D 10D 9RS 8S 7SR 4S 10N 9BS 0 8BS 4S 7S " 0.5 + 1.0 9BS 0 10D 10D     8RSB 8S 7RS 3BS 8BS 8BS 0 8BS 5SB 8SB " 0.5 + 2.0 10D 0 10D 10D 9BSR 8S     8SR 2SB 9RS 9BS 0 9BS 6SB 8SR " 0.5 + 3.0 10D 0 10D 10D 9BSR 8SR 8SR 4S     9RS 9BS 0 9BS 5S 7S " 0.5 + 4.0 10D 0 10D 10D 10D 10N 10N 4S 9RS 9BS 2S     9BS 6SB 8S " 1.0 + 1.0 10D 0 10D 10D 10D 10N 10D 6BS 5SB 9BS 0 9BS 9BS     9RS " 1.0 + 2.0 10D 2S 10D 10D 10D 9.5RS 10N 5BS 5SB 9BS 0 10D 9.5BS 8SR     " 1.0 + 3.0 10D 0 10D 10D 9BSR 9RS 9BSR 6BS 9RS 10D 1S 9BS 9.5BS 8S "     1.0 + 4.0 10D 0 10D 10D 10D 10N 10N 4SB 9RS 10D 0 9BS 9.5BS 9SR " 2.0 +     1.0 10D 3S 10D 10D 10D 10D 10D 9BS 7BS 10D 3S 9BS 9BS 9RS " 2.0 + 2.0     10D 4S 10D 10D 10D 10D 9SR 8BS 9RS 10D 5SB 9BS 10D 9S " 2.0 + 3.0 10D 3S     10D 10D 10D 10N 10N 9BS 8RS 10D 4S 9BS 10D 9SR " 2.0 + 4.0 10D 1S 10D     10D 10D 10D 9.8BSR 9BS 10N 10D 3S 10D 10D 10N Con- trol 0 0 0 0 0 0 0 0     0 0 0 0 0 0 0

    TABLE XVI      COMBINATION OF 1-METHOXY-6-CHLORO-2-TRIFLUOROMETHYL-1H-  IMIDAZO(4,5-b)P     EPIDINE ("A") WITH PROPAZINE ("B")              Fox-    Rates Morn-      Barn-  Large  tail Com- Lbs./ ing Pig- Rag- Sor- Velvet Lambs Jimson     yard  Crab- Sor- Mil-  Johnson pounds Acre Glory weed weed ghum Leaf     Quarter Weed Grass Rice grass ghum let Corn Grass       A + B 1/2 3/4 8DS 8SD 8BSD 0 3BSD 9RSD 9.5SD 5SD 2BS 3S 0 6BSD 0 8BSD     " 1/2 1 1/2 8.5BSD 8SD 9BSD 0 5BSD 9RSD 9BSD 4SD 3BS 4.5RS 0 7BSD 0 7BSD     " 1/2 3 8.5BSD 8.5SD 9BSD 0 3CS 8RSD 9.5BSD 8BSD 5BS 7.5RSD 0 6BSD 0     7.5BSD " 1 3/4 10D 8.5SD 9BSD 3BS 7.5BSD 8RSD 9.5SD 7BSD 1BS 9RSD 0     9.5SD 2S 9.5BSD " 1 1 1/2 10D 8SD 9.5BSD 3BS 10D 9RSD 9.5BSD 8.5BSD 2BS     8RSD 2BS 10D 0 9.5BSD " 1 3 10D 8.5SD 10D 2BS 10D 9RSD 9.5BSD 9.5BSD 4BS     9RSD 1BS 9SD 0 9.5BSD " 1 1/2 3/4 10D 8SD 8BSD 2BS 8BSD 9RSD 9.5SD 10D     6BSD 9.5RSD 2BS 10D 0 10D " 1 1/2 1 1/2 9.5BSD 8BSD 10D 2.5BS 9.5BSD     9RSD 9.5BSD 9BSD 5BSD 10D 2BS 10D 2BS 9.5BSD " 1 1/2 3 10D 8BSD 10D 3BS     10D 9RSD 10D 9.5BSD 7BSD 8SD 3.5BS 10D 1S 9.5BSD " 2 3/4 10D 8BSD 9BSD     3BS 9.5BSD 9RSD 9.5BSD 9.5BSD 5BSD 9.5SD 4BS 10D 2S 10D " 2 1 1/2 10D     8BSD 9.5BSD 2BS 10D 9.5RSD 10D 10D 6.5BSD 10D 3BS 10D 1S 9BSD " 2 3 10D     8.5BSD 10D 2BS 9BSD 9.5RSD 9.5BSD 10D 6BSD 9RSD 2BS 10D 0 10D Control --     -- 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Control -- -- 0 0 0 0 0 0 0 0 0 0 0 0 0 0     Control -- -- 0 0 0 0 0 0 0 0 0 0 0 0 0 0

    TABLE XVII      COMBINATION OF 1-METHOXY-6-CHLORO-2-TRIFLUOROMETHYL-  1H-IMIDAZO(4,5-b)P     YRIDINE ("A") WITH SIMAZINE ("B")              Fox-    Rates Morn-     Barn-  Large  tail Com- Lbs./ ing Pig- Rag-  Velvet Lambs Jimson yard     Crab-  Mil- Sor- Johnson pounds Acre Glory weed weed Corn Leaf Quarter     Weed Grass Rice grass Corn let ghum Grass       A + B 1/4 1/4 6.5BSD 8.5BS 6.5SD 0 2S 6.5S 9.5SD 0 1BS 6BS 0 4.5BS 0     4BS " 1/4 1/2 10D 7BSD 7RSD 0 5CS 10D 10D 6BSD 2BS 7.5BS 0 6BS 0 7BSD "     1/4 1 10D 8.5BSD 9SD 0 6CS 9SD 9.5SD 8BSD 2BS 9BSD 0 7BSD 7BSD 9BSD "     1/4 2 10D 8.5BSD 9SD 0 8SD 9.5SD 10D 9.5BSD 3BS 9BSD 6BSD 9.5BSD 2S 9BSD     " 1/2 1/4 10D 8BS 8BSD 0 5CS 9BSD 9SD 3BS 1B 6SD 0 7.5BSD 0 8.5BSD " 1/2     1/2 9.5BSD 8.5BS 9.5SD 0 6.5BSD 9BSD 9.5SD 3BS 6.5BS 8SD 0 8BSD 0 9BSD "     1/2 1 9.5BSD 9BS 9.5SD 0 6.5BSD 10D 10D 3.5BS 5BS 9SD 0 9.5BSD 0 9.5BSD     " 1/2 2 10D 9.5BS 10D 0 7CSD 10D 10D 9.5BS 5BS 9.5SD 0 10D 4BS 9.5BSD "     1 1/4 9.5BSD 9BS 9SD 0 7SD 9BS 10D 7BSD 3BS 9BSD 0 9BSD 0 10D " 1 1/2     10D 6.5S 9SD 1S 6SD 9BS 9.5BSD 9.5BSD 2BS 9.5BSD 1.5S 9.6BSD 3BS 10D" 1     1 10D 8S 10D 0 7SD 7.5BS 9.5BSD 9.5BSD 6BS 10D 0 9.5BSD 3BS 10D " 1 2     10D 9.5BS 8SD 1S 9SD 10D 10D 9BSD 4BS 10D 1.5S 10D 5BS 10D " 2 1/4 10D     9BSD 9.5BSD 1.5S 10D 10D 10D 9BSD 6BSD 9.5BSD 0 10D 3BS 10D " 2 1/2 10D     9.5BSD 9.5BSD 2S 9.5BSD 9BS 9.5SD 9BSD 6BSD 9.5BSD 1.5S 10D 5BS 9.5BSD "     2 1 10D 9.5BSD 9.5BSD 1S 9BSD 9.5BS 10D 9.5BSD 6BSD 10D 1S 10D 4.5BS     9.5BSD " 2 2 9.5BSD 9BSD 9.5BSD 1.5S 9.5BSD 10D 10D 9.5BSD 6BSD 10D 1S     10D 6BS 9.5BSD Control -- -- 0 0 0 0 0 0 0 0 0 0 0 0 0 0

    TABLE XVIII       COMBINATION OF 1-METHOXY-6-CHLORO-2-TRIFLUOROMETHYL-  1H-IMIDAZO(4,5-b)     PYRIDINE ("A") WITH TRIFLURALIN ("B")           Fox-             Rates Morn-  tail  Barn- Large Com- Lbs./ ing     Mil- Rag- yard Crab- Pig- Sor-  Velvet  Jimson Johnson Lambs pound Acre     Glory Corn let weed Grass grass weed ghum Rice Leaf Corn Weed Grass     Quarter       A + B 0.21 0.25 6SB 0 8SR 5S 9RS 10N 10N 8SR 5SC 0 0 2S 5SR 4S " " 0.5     8SB 0 9SR 10D 9RS 9.5RS 10N 7SR 6SC 3SB 0 5SB 4S 5S " " 1.0 10D 0 9BSR     10D 9RSB 9.5RS 9.5BS 9SR 5SCB 8BS 2S 8BS 9.5RS 8BSR " " 2.0 10D 5S 10N     10D 9.5RS 9.5RS 10N 8SR 5SB 10D 4S 9BSR 10N 10N " 0.42 0.25 5SB 4S 9RSB     5SB 10N 10N 10N 10N 8SC 2S 4SC 2SC 9.5RS 6SR " " 0.5 6BS 5S 9.8RS 10D     9.5RS 9.5RS 10N 10N 9SC 3S 4S 5SB 10N 8SR " " 1.0 10D 4S 9.8RS 10D 10N     10N 10N 9.8RS 8SC 10D 5SB 9BS 9.5RS 9RS " " 2.0 10D 5S 10N 10D 10N 10N     10N 10N 8SCR 10D 5SC 9BS 9.5RS 10N " 0.83 0.25 6SB 7FSC 10N 7RS 9.5RS     10N 10N 10N 9CSR 3S 7CSF 3S 9.5RS 8RS " " 0.5 7BS 8RSF 10N 10D 10N 10N     10N 9.9RS 9CSR 4SB 7CSF 8BSF 9.8RS 9.5RS " " 1.0 8SB 8BSF 9.8RS 10D     9.8RS 10N 10N 10N 9SRF 7BS 7SC 9.5BS 9.9RS 9.5RS " " 2.0 9BS 8SCB 10N     10D 10N 10N 10N 10N 9SCR 9.8BS 7SCB 9BSF 10N 9.5RS " 2.0  0.25 7SB 9RSF     10N 8BSR 10N 10N 10N 10N 9.5SR 6S 9RSF 4SB 10N 10N " " 0.5 7SB 9RSB 10N     9.5BS 10N 10N 10N 10N 9.8RS 5SF 8FSB 6SF 10N 10N " " 1.0 10D 9FSB 10N     10D 10N 10N 8SR 10N 9RS 10D 9SF 9.5BS 10N 9.5RS " " 2.0 10D 9FSB 10N 10D     10N 10N 9.5RS 10N 9.5SR 9.5BS 9FSB 10D 10N 10N Control 0  0 0 0 0 0 0 0     0 0 0 0 0 0 0

    TABLE XIX      COMBINATION OF 1-METHOXY-6-CHLORO-2-TRIFLUOROMETHYL-  1H-IMIDAZO(4,5-b)P     YRIDINE ("A") WITH TCA ("B")              Fox-    Rates Morn-     Barn-  Large  tail Com- Lbs./ ing Pig- Rag-  Velvet Lambs Jimson yard     Crab-  Mil- Sor- Johnson pound Acre Glory weed weed Corn Leaf Quarter     Weed Grass Rice grass Corn let ghum Grass       A + B 1/4 3/4 2CS -- -- 1S 0 0 2.5S 1S 0 1S 0 4BFD 0 3BS " 1/4 1 1/2     2CS -- -- 2S 0 2S 4S 0 5BS 8SD 0 7BFD 0 3BS " 1/4 3 2CS -- -- 1S 0 3RS     2S 2S 9BSD 9BSD 0 9BFD 0 4BS " 1/4 6 1C -- -- 1S 0 3S 3S 7BFS 10D 7BSD 0     9.5BFD 7BFD 8BSD "1/2 3/4 3BS -- -- 0 0 2S 7BSD 3S 6BSD 5BS 0 8.5BSD 0     4BS " 1/2 1 1/2 5BS -- -- 0 4CS 3S 6BSD 4BS 5BS 3BS 0 7BSD 0 8BSD " 1/2     3 4BSD -- -- 0 5CBS 8RS 10D 8BSD 8BS 5SD 0 7BFSD 3BFS 9BSD " 1/26     7BSD----3FS6BSD8RSD 9BSD 6BSD8BSD7BSD2FS 9.5BSD8BFSD9BSD" 1 3/49BSD----0     7BSD 7RS 9BSD 7BSD 3BS 6BSD 1S 8BSD 0 8BSD " 1 1 1/2 9BSD -- -- 0 5BS     7RS 9.5BSD 9BSD 8.5BSD 9BSD 1.5S 9BSD 3BS 9BSD " 1 3 5CBS -- -- 0 6CBS     4RS 9BSD 6BSD 7BSD 9BSD 2S 10D 3BS 8BSD " 1 6 6BCSD -- -- 1S 8BSD 8RS     9BSD 9BSD 9BSD 9BSD 0 9.5BSD 6BFS 10D " 2 3/4 10D -- -- 2S 9BSD 7RS     9.5BSD 9.5BSD 6BSD 8BSD 1S 7BSD 3BS 9BSD " 2 1 1/2 10D -- -- 1S 9BSD 7RS     9.5BSD 9.5BSD 6BSD 9BSD 2S 10D 3BS 9.5BSD " 2 3 10D -- -- 3S 9BSD 8RS     9BSD 9.5BSD 7BSD 8BSD 0 10D 6BSD 9.5BSD " 2 6 10D -- -- 4FS 10D 9RS 9BSD     9.5BSD 9BSD 8.5BSD 3FS 10D 8.5BSFD 10D Control -- -- 0 -- -- 0 0 0 0 0 0     0 0 0 0 0

EXAMPLES 104-107

Additional evaluations were conducted, in accordance with the proceduresof the foregoing examples, with1-methoxy-5-chloro-2-trifluoromethyl-1H-imidazo(4,5-b)pyridine and with1-methoxy-2,6-bis(trifluoromethyl)-1H-imidazo(4,5-b)pyridine. Each wasemployed in combination with alachlor and separately in combination withatrazine. The results were as set forth in the following tables.

    TABLE XX      COMBINATION OF 1-METHOXY-5-CHLORO-2-TRIFLUOROMETHYl-  1H-IMIDAZO(4,5-b)P     YRIDINE ("A") WITH ALACHLOR ("B")     Fox-             Rates Morn-  tail      Barn- Large Com- Lbs./ ing  Mil- Rag yard Crab- Pig- Sor-  Velvet     Jimson Johnson Lambs pounds Acre Glory Corn let weed Grass grass weed     ghum Rice Leaf Corn Weed Grass Quarter       A + B 0.25 + 0.5 3SE 2S 9.5BS 9.5RS 9.5RS 10D 9.5RS 9RSF 9RS 9.5BS 0     9BS 9RSB 10D " 0.25 + 1.0 4SE 0 10D 10D 10D 10D 10D 9RSF 9.8RS 8BS 0     9.5BS 9RSB 10D " 0.25 + 2.0 6BSC 2S 10N 10N 10D 10N 10N 9.5BS 10N 9BS 1S     10D 9.5BS 10N " 0.25 + 4.0 9.5BS 0 10D 10D 10N 10N 10N 9.5BS 10N 9.5BS     3S 10D 10D 10D " 0.5 + 0.5 9.5BS 2BS 10D 9RS 9RSB 9.5RS 10N 8SFB 9.5RS     10D 2S 10D 8RSB 9.5RS " 0.5 + 1.0 9BS 0 10D 10D 9.5RS 10D 10N 9.5BS 10N     10D 0 10D 8BSR 9RS " 0.5 + 2.0 10D 2S 10D 10D 10D 10N 10N 9.8BS 10N 10D     2S 10D 9.5RSB 9.5BS " 0.5 + 4.0 10D 0 10N 10D 10N 10N 10N 10D 10N 10D 2S     10D 10D 10D " 1.0 + 0.5 10D 0 10D 10D 10D 10N 10D 9.8BS 9.5RS 10D 1S 10D     8RSB 10D " 1.0 + 1.0 10D 2S 10D 10D 10N 10N 9.5RS 8BSF 10D 10D 0 10D     9.5BS 9.5RS " 1.0 + 2.0 10D 1S 10D 10D 10N 10N 10N 9.8BS 10N 10D 2S 10D     9.5BS 10N " 1.0 + 4.0 9.8BS 2SB 10N 10N 10N 10N 10N 9.8BS 10N 10D 2SB     10D 10D 10D " 2.0 + 0.5 10D 0 10D 10D 10D 10D 10D 9BSF 9RSB 10D 0 10D     9BSR 10D " 2.0 + 1.0 10D 2S 10D 10D 10D 10N 10D 10D 8RSB 10D 0 10D 10D     10D " 2.0 + 2.0 10D 3S 10N 10D 10N 10N 10N 10D 10N 10D 4SB 9BSR 9.5RS     10D " 2.0 + 4.0 10D 3S 10D 10N 10N 10N 10N 10D 10N 10D 2S 10D 9.5BS 10N     Control 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

    TABLE XXI      COMBINATION OF 1-METHOXY-5-CHLORO-2-TRIFLUOROMETHYL-  1H-IMIDAZO(4,5-b)P     YRIDINE ("A") WITH ATRAZINE ("B")     Fox-             Rates Morn-  tail      Barn Large Com- Lbs./ ing  Mil- Rag- yard Crab- Pig- Sor-  Velvet     Jimson Johnson Lambs pounds Acre Glory Corn let weed Grass grass weed     ghum Rice Leaf Corn weed Grass Quarter       A + B 0.25 + 0.25 7BS 1S 7BS 10D 6SB 4SB 6SB 0 5B 8BS 0 10D 0 7SB "     0.25 + 0.5 8BS 0 7BS 10D 5SB 3SB 7SB 0 5B 9BS 0 9BS 0 7SB " 0.25 + 1.0     10D 0 8BS 10D 9BS 8BS 8BS 0 5B 10D 0 10D 2S 8BS " 0.25 + 2.0 10D 0 9BS     10D 8BS 7BS 7BS 0 9B 10D 0 10D 2SB 9BS " 0.5 + 0.25 9BS 0 9BS 10D 7SB     8BS 8BS 0 8B 10D 0 10D 3SB 8BS " 0.5 + 0.5 10D 0 10D 10D 7BS 5SB 8BS 1S     6B 7.5BS 0 10D 3SB 9BS " 0.5 + 1.0 10D 2C 9.5BS 10D 7BS 6BS 8BS 2S 5B     10D 3SC 9BS 3SC 10D " 0.5 + 2.0 10D 0 9.5BS 10D 9BS 7BS 9BS 1S 9B 10D 0     10D 3S 9BS " 1.0 + 0.25 10D 1S 9.5BS 10D 9BS 6BS 9BS 2S 8B 10D 0 10D 3S     9BS " 1.0 + 0.5 10D 2SB 10D 10D 9.5BS 7SB 8BS 3SB 9B 10D 0 10D 4SB 9BS "     1.0 + 1.0 10D 1SB 10D 10D 9.5BS 9BS 9BS 3SB 10D 10D 0 10D 4SB 9BS " 1.0     + 2.0 10D 3S 10D 10D 9BS 7BS 9BS 5SB 10D 10D 1S 10D 3SB 9BS " 2.0 + 0.25     10D 4SB 10D 10D 9.5BS 8BS 9BS 8BS 10D 10D 3SB 10D 9BS 9BS " 2.0 + 0.5     10D 4SB 10D 10D 9.5BS 9.5BS 9.5BS 8BS 9.5BS 10D 3S 10D 5SB 9BS " 2.0 +     1.0 10D 6SB 10D 10D 9BS 9.5BS 9.5BS 8BS 10D 10D 2S 10D 5SB 10D " 2.0 +     2.0 10D 3S 10D 10D 10D 9.8BS 9.5BS 8SB 9B 10D 3S 10D 6SB 9BS Control 0 0     0 0 0 0 0 0 0 0 0 0 0 0 0

    TABLE XXII      COMBINATION OF 1-METHOXY-2,6-BIS(TRIFLUOROMETHYL)-  1H-IMIDAZO(4,5-b)PYR     IDINE ("A") WITH ALACHLOR ("B")     Fox-             Rates Morn-  tail     Barn- Large Com- Lbs./ ing  Mil- Rag- yard Crab- Pig- Sor-  Velvet     Jimson Johnson Lambs pound Acre Glory Corn let weed Grass grass weed     ghum Rice Leaf Corn Weed Grass Quarter       A + B 0.25 + 0.5 2E 0 9.5BS 4SB 9RS 7RSB8BSR 1S 5RB 4SB 0 3SB 4SR 9RS     " 0.25 + 1.0 3SFE 0 10D 6SB 9.5RS 10D 10D 5SF 8RS 5SB 0 5SB 7RS 9RS "     0.25 + 2.0 5SEF 0 10D 9.5BS 10N 10D 10N 5SF 9RS 5SB 0 6SB 9RS 9RSB "     0.25 + 4.0 7SBF 3SF 10N 9.5RS 10D 10D 10D 7SFB 10N 8SB 2S 8BS 10D 10N "     0.5 + 0.5 5SBF 0 10D 5SB 9RS 8RSB 10D 3SB 7SRB 7BS 0 8BS 7RSF 8SR " 0.5     + 1.0 6SBF 10D 7SR 9.5RS 10D 10D 3SF 9RSB 9.5BS 0 9BS 7RSB 9BSR "0.5 +     2.09.5BS1S 10D 10N 10D 10N 10N 8BSF 9.5RS 9BS 1S 9BS 9.5BS 10N " 1.0 +     0.5 9.5BS 0 10D 6S 7SR 9RSB 10D 4SFB 4S 9BS 0 9BS 8BS 9RS " 1.0 + 1.0     8BS 0 10D 7RS 9RS 9RSB 10D 8BSF 9RS 9BS 0 9.5BS 9.5BS 9.5RS " 1.0 + 2.0     9.5BS 3SB 10N 8RS 10D 10D 10N 8RSB 10N 9.5BS 3S 9.5BS 9.5RS 9.5RS " 1.0     + 4.0 10N 0 10N 9SR 10N 10N 10D 9.5RS 10N 9BS 3S 9BS 10D 9.5RS " 2.0 +     0.5 10D 0 10D 8BS 9RS 8BS 9BSR 8BS 8RS 9.5BS 2S 9BS 9BSR 9.5RS " 2.0 +     1.0 10D 3S 10D 7S 9.5RSB 9.5BS 10D 8BS 9RS 9BS 1SB 9.5BS 9.5BS 9.5RS "     2.0 + 2.0 10D 3S 10D 8SR 9.5BS 10D 10D 9BSF 9.5RS 9.5BS 4S 9.5BS 10D 10N     " 2.0 + 4.0 10D 3SB 10N 10D 10N 10N 10N 9BSF 9.5RS 9.5BS 3S 9.5BS 10D     10N Control 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0      ]

                                      TABLE XXIII                                 __________________________________________________________________________    COMBINATION OF 1-METHOXY-2,6-BIS(TRIFLUOROMETHYL-                             1H-IMIDAZO(4,5-b)PYRIDINE ("A") + ATRAZINE ("B")                                                Fox-                                                             Rates Morn-  tail    Barn-                                                                             Large                    John-                                                                             Lambs              Com- Lbs./ ing    Mil-                                                                              Rag-                                                                              yard                                                                              Crab-                                                                             Pig-                                                                             Sor-   Velvet Jimson                                                                            son Quart-             pounds                                                                             Acre  Glory                                                                             Corn                                                                             let weed                                                                              Grass                                                                             grass                                                                             weed                                                                             ghum                                                                              Rice                                                                             Leaf                                                                              Corn                                                                             Weed                                                                              Grass                                                                             er                 __________________________________________________________________________    A + B                                                                              0.25 + 0.25                                                                         3BS 0  3B  2S  0   2S  5SB                                                                              0   2B 2S  0  2B  0   7BS                "    0.25 + 0.5                                                                          5BS 0  4B  8BS 4S  4SB 6BS                                                                              0   3B 4SB 2S 8BS 0   8BS                "    0.25 + 1.0                                                                          10D 0  7BS 8BS 3SB 4SB 8BS                                                                              1B  7B 10D 0  9BS 1B  8BS                "    0.25 + 2.0                                                                          10D 0  9BS 10D 8BS 6BS 8BS                                                                              0   8B 10D 0  10D 2B  7BS                "    0.5 + 0.25                                                                          9BS 0  3B  4BS 3SB 6BS 7SB                                                                              0   5B 4SB 2S 8BS 0   6SB                "    0.5 + 0.5                                                                           9BS 0  4B  6S  4S  4S  6SB                                                                              0   6B 5SB 0  10D 2S  7SB                "    0.5 + 1.0                                                                           10D 0  5BS 10D 4SB 5SB 7BS                                                                              0   7B 9BS 0  10D 0   7SB                "    0.5 + 2.0                                                                           8BS 4SB                                                                              5BS 10D 7BS 7BS 8SB                                                                              0   5B 10D 0  9BS 2S  7BS                "    1.0 + 0.25                                                                          9.5BS                                                                             0  7BS 4SB 4S  5SB 3SB                                                                              0   0  8BS 0  9BS 2S  8BS                "    1.0 + 0.5                                                                           10D 0  7BS 7SB 4S  5SB 8SB                                                                              1B  3BS                                                                              9.5BS                                                                             0  9BS 2S  8BS                "    1.0 + 1.0                                                                           9.5BS                                                                             0  7BS 8BS 5SB 5SB 8BS                                                                              1B  5B 10D 1S 9.5BS                                                                             1S  9SB                "    1.0 + 2.0                                                                           10D 0  9.5BS                                                                             9SB 8BS 8BS 8BS                                                                              3SB 8B 9.5BS                                                                             0  9.5BS                                                                             2SB 9BS                "    2.0 + 0.25                                                                          9.5BS                                                                             0  8BS 8BS 5SB 8BS 8BS                                                                              4B  5B 9BS 0  9BS 3BS 8BS                "    2.0 + 0.5                                                                           10D 0  8BS 9BS 4B  6BS 8SB                                                                              3BS 5B 9BS 2S 9BS 4BS 9BS                "    2.0 + 1.0                                                                           10D 0  8BS 10D 5SB 7BS 8SB                                                                              2B  7B 10D 2S 10D 4SB 8BS                "    2.0 + 2.0                                                                           10D 0  8BS 10D 8BS 7BS 8SB                                                                              5B  7B 10D 3S 10D 4B  9BS                Control                                                                            0     0   0  0   0   0   0   0  0   0  0   0  0   0   0                  __________________________________________________________________________

EXAMPLES 108-110

1-Methoxy-6-chloro-2-trifluoromethyl-1H-imidazo(4,5-b)pyridine wasevaluated separately in combination with each of alachlor, atrazine, andpropachlor. The evaluations were conducted under field conditions at alocation in the southern coastal plain. The compounds were formulated bytank-mixing a commercial application of the respective known herbicidewith an emulsifiable concentrate of the1-methoxy-6-chloro-2-trifluoromethyl-1H-imidazo(4,5-b)pyridine. Thetank-mixed formulation was then applied to the soil surface immediatelyafter planting with corn. Prior to planting, the plots had beenbroadcast with foxtail millet (Setaria italica) and sicklepod (Cassiaobtusifolia) and disced. However, additional weed seeds, including weedseeds of each of the named species, were present as a naturalinfestation of the plots. The growing conditions were typical for thearea. Evaluations were made of corn injury and stand reduction, also ofthe control of the weed species. There were three replications pertreatment pattern, and the ratings were averaged for the threereplications. Results are given in the following table for standreduction.

                                      TABLE XXIV                                  __________________________________________________________________________    COMBINATION OF 1-METHOXY-6-CHLORO-2-TRIFLUOROMETHYL-                          1H-IMIDAZO(4,5-b)PYRIDINE ("A") WITH                                          ALACHLOR ("B"), ATRAZINE ("C"), AND PROPACHLOR ("D")                          Rate      Reduction                                                                           Percent                                                       in        in    Corn      Percent Weed Control                                Treat-                                                                            Lbs./ Emergence                                                                           Injury    Foxtail Millet Sicklepod                            ment                                                                              Acre  (10 Days)                                                                           23 Days                                                                            64 Days                                                                            16 Days                                                                            24 Days                                                                            42 Days                                                                            16 Days                                                                            24 Days                                                                            42 Days                    __________________________________________________________________________    A   1.0   0     0    3    61   88   90   14   14   ↑                    "   1.5   0     0    0    33   92   98   14   0    ↑                    "   2.0   9     13   17   11   100  100  0    0    ↑                    "   3.0   10    17   23   56   100  100  0    0    ↑                    B   2.0   3     0    0    67   62   97   0    0    ↑                    A + B                                                                             0.75 + 0.75                                                                         0     0    0    89   83   95   14   0    ↑                    "   0.75 + 1.0                                                                          2     0    0    100  96   98   14   57   ↑                    "   1.0 + 1.0                                                                           0     0    0    100  96   100  0    0    ↑                    "   1.0 + 1.5                                                                           6     0    0    94   100  100  14   71   ↑                    "   1.5 + 2.0                                                                           0     0    0    100  100  100  29   0    ↑                    C   2     4     0    7    11   33   88   0    57   NO    ↑              A + C                                                                             0.75+ 0.75                                                                          0     0    0    44   79   97   0    14   READING                    "   0.75 +1                                                                             0     0    3    44   79   98   0    14   MADE                       "   1 + 1 0     0    0    72   96   100  29   43   ↓                   "    1 + 1.5                                                                            0     0    0    61   96   100  57   86   ↓                   "   1.5 + 2                                                                             0     0    7    50   100  100  43   86   ↓                   D   5     0     0    0    72   100  95   14   0    ↓                   A + D                                                                             0.75 + 2                                                                            10    0    7    100  92   97   0    0    ↓                   "   0.75 + 3                                                                            0     0    0    100  100  100  14   29   ↓                   "   1 + 2 0     0    0    100  96   100  29   29   ↓                   "   1 + 3 0     0    0    100  100  100  14   0    ↓                   "   1 + 5 13    0    0    100  100  100  29   0    ↓                   __________________________________________________________________________

The compounds of the present invention can also be employed as thestarting materials in a reaction to prepare yet other compounds usefulas herbicides. In general, this reaction comprises the treatment of oneof the compounds of the present invention with a nucleophilic reagent,the reaction results in loss of the 1--OR³ moiety and introduction ofthe nucleophilic ion into the pyridine ring, or in reduction. Suitablenucleophilic reagents are compounds containing an amine group, in thecase of those present compounds which are ethers; and compoundscontaining a halide ion, in the case of those of the present compoundswhich are esters, including the carbamate and sulfonate esters. Theoverall reaction scheme can be summarized as follows: ##STR9##Rearrangement is the course of reaction except where a bromide or iodideis employed, in which case, reduction occurs. The introducednucleophilic moiety locates at either the 5 or 7 positions, depending onthe identity of R² and the nucleophilic moiety.

In the instance of either reduction or introduction of the nucleophile,the products are useful, in accordance with prior teachings, asherbicides. See U.S. Pat. No. 3,459,759.

Two synthetic routes are useful in the preparation of the starting1-hydroxy compounds: ##STR10## In a first synthetic route, the compoundsare prepared by reduction of a precursor of the formula: ##STR11## Thereaction is believed to go through several intermediates which are notisolatable, but yields as product the desired1-hydroxy-1H-imidazo(4,5-b) pyridine compound. The reaction conditionsare not critical; however, it is generally preferred to employ asreducing agent two moles of hydrogen per mole of the nitropyridineamine,in the presence of a minor amount of a catalyst comprising a noblemetal, preferably palladium. In a representative synthesis,1-hydroxy-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine wasprepared as follows:

5-Chloro-3-nitro-2-(trifluoriacetamido)pyridine (2.0 grams) washydrogenated with two moles of hydrogen in ethanol containing 0.5 gramof 5 percent palladium on carbon. The resulting reaction mixture wasfiltered and evaporated to separate the desired6-chloro-1-hydroxy-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridinecompound which, after recrystallization from benzene melted at 268°-70°C.

Analysis, Calc.: C, 35.39; H, 1.27; N, 17.69. Found: C, 35.59; H, 1.45;N, 17.77.

In a second route, a suitable 1-hydroxy compound ##STR12## is itselfutilized as a precursor to other 1-hydroxy compounds which serve asstarting materials for the preparation of the compounds of the presentinvention. In this route, the initially employed 1-hydroxy compound issubjected to reactions to introduce onto the pyridine ring one or moredesired groups and/or to convert one or more substituents alreadypresent on the pyridine ring to the desired group or groups.

Thus, for example, the 1-hydroxy compound can be halogenated or nitratedat a position or positions previously unsubstituted. A nitro groupalready present can be reduced to an amino group; and an amino groupalready present can also be oxidized back to a nitro group. An aminogroup can also be diazotized and replaced by, for example, a halo group,a nitrile group, or a loweralkylthio group. Oxidation of theloweralkylthio-substituted compound yields the correspondingloweralkylsulfonyl-substituted compound. The fluorinated groups (R² =--CF₃, --CF₂ Cl, or --CF₂ H) are readily obtained initially byconversion of a nitrile to a carboxyl group; subsequent treatment withSF₄ in the presence of HF yields the --CF₃ group. Alternately,conversion to an aldehyde and treatment with SF₄ alone yields the --CF₂H group; and subsequent chlorination converts the --CF₂ H group to thecorresponding --CF₂ Cl group. An alkyl substituent is introduced byreaction of an alkyl lithium with a halo-substituted 1-hydroxy compound;and a perfluoroalkyl substituent is introduced by reaction of ahalo-substituted 1 -hydroxy compound with a perfluoroalkyl iodide in thepresence of copper. These and numerous other conversion substitutionreactions are well known to those skilled in the art. Attention isdirected to Fieser and Fieser, Advanced Organic Chemistry (ReinholdPublishing Corp,, New York, N.Y., 1961), especially chapters 9 and 17.See also Wagner and Zook, Synthetic Organic Chemistry (John Wiley andSons, Inc., New York, N.Y., 1953).

As will be understood by those skilled in the art, more than one of theforegoing reactions will be needed to complete the preparation of someof the compounds of the present invention; and in the case of allreactions, due consideration must be given to the orienting effect ofsubstituent groups. Also, for those of the foregoing reactions whichutilize a nucleophilic reagent, it may be necessary that the 1-hydroxygroup first be converted to an ester or ether, as discussed hereinabove;and the reaction with nucleophilic reagent then conducted.

Preferred compounds of the present invention are those which aremonosubstituted (n = 1) and the substituent (R²) is halogen, nitro,--CF₃, --CF₂ Cl, --CF₂ H, or loweralkylsulfonyl of C₁ -C₄.

A particularly preferred sub-genus of the compounds of the presentinvention is defined as follows: ##STR13## wherein R⁸ represents halo or--CF₃ ; R⁹ represents loweralkyl of C₁ -C₄, loweralkenyl of C₂ -C₄,benzyl, loweralkanoyl of C₂ -C₄, loweralkenoyl of C₃ -C₄, benzoyl,loweralkylsulfonyl of C₁ -C₄, or carbamoyl of the formula ##STR14##wherein X represents oxygen or sulfur, and one R⁴ represents phenyl,loweralkyl of C₁ -C₄, or loweralkenyl of C₂ -C₄, and the other R⁴represents hydrogen, loweralkyl of C₁ -C₄, or loweralkenyl of C₂ -C₄,subject to the limitation that both R⁴ moieties taken together do notcontain more than six carbon atoms, or both R⁴ moieties taken togetherrepresent straight-chain alkylene of C₂ -C₆, both inclusive; and R¹⁰represents trifluoromethyl, pentafluoroethyl, or1,1,2,2-tetrafluoroethy.

I claim:
 1. A compound of the formula ##STR15## wherein R¹ represents hydrogen, chlorine, fluorine, difluoromethyl, perfluoroalkyl of C₁ -C₆, or radical of the formula: ##STR16## wherein each Z independently represents hydrogen or halogen and m represents 0 or 1; R² represents halogen, nitro, --CF₃, --CF₂ Cl, --CF₂ H, or loweralkylsulfonyl of C₁ -C₄ ; and R³ represents
 1. radical of the formulae ##STR17## wherein X is oxygen or sulfur; or
 2. --SO₂ --R⁷ wherein R⁷ is loweralkyl as above defined, cycloalkyl of C₅ -C₆, phenyl, substituted phenyl or benzyl, wherein substituted phenyl is a phenyl radical bearing from 1-3 substituents, each of which is independently amino, nitro, chloro, methyl, or methoxy.
 2. The compound of claim 1 which is 1-(methylsulfonyloxy)-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine. 